It's 3 a.m. at the Nahar Shalom Yeshiva, next to Jerusalem's Mahaneh Yehuda open-air market. A handful of Kabbala students begin their daily regime of study and prayer. "Kingdom receives solely from Foundation, through whom she receives from them all [all 10 emanations, or sefirot]," recites a young student of Kabbala named Moshe Yitzhak. "Without Foundation she cannot receive from any of them, and without Kingdom none of the emanations can transmit to the lower worlds, for she is the essence of those worlds, conducting them." The language is Hebrew, but what Moshe Yitzhak is saying is impenetrable. It's as if he were reading from a technical manual explaining the intricacies of a particularly complicated piece of machinery that has no known function and that has never been seen, let alone operated. These teachings - of Rabbi Yitzhak Ashkenazi Luria (the Arizal), as explicated by Rabbi Haim Vital and Luria's other intellectual and spiritual heirs - are well-nigh incomprehensible for the uninitiated. And even those who have been studying Lurianic Kabbala for many years understand what they learn in a very abstract, almost intuitive way, say long-time students. Why does Moshe Yitzhak study them? "I want to strengthen my faith," he says. "I want to see how God directs His will in the world, how divine emanations are channeled into our world. What is man's mission in the world? What does God want from me? In Kabbala I found real answers - answers that were deeper than what I found in conventional Torah learning. " Yet Moshe Yitzhak cannot easily explain an idea from Kabbala. "In order to understand it you have to try it. You have to taste it," he says. "It is not something that can be explained. It is something that must be experienced." ENTHUSIASM FOR Judaism's esoteric knowledge is not new; in secular and gentile circles, Kabbala has been seized upon like popsicles on a hot summer day. As the outside world knows it, Kabbala is the spiritual pursuit du jour for stars such as Madonna, Demi Moore, Ashton Kutcher, Sandra Bernhard and Roseanne Barr; there are myriad Web sites offering Gnostic Kabbala, Kabbala that incorporates Tantric meditations, New Age Kabbala, Kabbala that sparks political activism or self-activism and Kabbala that encourages greater ecological sensitivity. All of this is foreign to the haredi yeshiva world, where Moshe Yitzhak is something of an oddity. Besides a few places like Nahar Shalom, the vast majority of yeshivot and kollelim (study halls for married men) continue to hammer away at the same age-old texts: Mishna, Gemara, Halacha. In haredi neighborhoods of Jerusalem such as Mea She'arim and Geula, there is no mention of Kabbala: no classes for the masses, no rebukes for ignoring the Kabbala, no quotes by famous rabbis encouraging the learning of Kabbala. Around the world in Rabbi Phillip Berg's Kabbala Centers, 5 million non-Orthodox Jews and gentiles have attended classes, according to the center's Web site. Rabbi Michael Laitman, head of the Bnei Baruch Kabbala and Education Research Center, regularly packs halls in the US with hundreds of Americans - Jews and gentiles alike - interested in learning Kabbala. But don't look for Kabbala in the curriculum at the great haredi yeshivot such as Mir, Hebron and Ponevezh. And while publishing giants like Simon and Schuster and Random House publish kabbalistic books by the likes of Rabbi David Aaron of the Old City, there are no plans at Artscroll publications - an Orthodox operation with a rabbinic advisory board that prints books on Judaism - to print kabbalistic works. "I admit it could be very lucrative," says Shmuel Blitz, who heads Artscroll's Israel operations. "But our spiritual advisers think Kabbala is not something that should be made available to the masses. If someone is learning Kabbala seriously he is not an Artscroll client - and if he is an Artscroll client, chances are he is not ready for Kabbala." Or, as haredi historian Rabbi Shimon Yosef Meller puts it: "Real kabbalists are so secretive that nobody knows they are kabbalists, and those who are known as kabbalists are probably not real kabbalists." BUT UNDERNEATH the surface, a miniature revolution is taking place. Moshe Yitzhak is not alone. "A few decades ago, the only place a married yeshiva guy could go to learn Kabbala was at Rabbi Ya'acov Hillel's yeshiva [Ahavat Shalom] at 2 a.m.," says an important haredi rabbi. "But today there are Kabbala classes all over at all times of the day." Jerusalem's tiny Mekor Baruch neighborhood is a thriving Kabbala center that caters mainly to the haredi community. Rabbi Yosef Berlinger offers classes (in Yiddish) at Sha'ar Hashamayim. Rabbi Mordechai Attia teaches at Yeshivat Hahaim Vehashalom to a diverse group, many of whom are haredi yeshiva students. Rabbi Shmuel Darzi, who passed away in January, taught at Nayot Be'rama Yeshiva. Twice a week, Rabbi David Batzri, head of Yeshivat Hashalom, teaches Kabbala to men who have spent a good part of their lives learning Gemara, many of whom are teachers and rabbinical judges. There is also Yeshivat Beit El, one of the oldest Kabbala yeshivot in Israel, located on Rehov Rashi in Mekor Baruch, where the centenarian kabbalist Rabbi Yitzhak Kadouri first studied when he arrived in the Land of Israel from Baghdad at the age of 17. These yeshivot, all located within a few blocks of each other, by no means make up an exhaustive list. In Jerusalem's Beit Yisrael neighborhood there is Rabbi Ezriel Mansour's Yeshivat Shuvi Nafshi, and the hassidic Anshei Ma'amad. There are also new kollelim such as Sha'arei Hakedusha Vehatefila, headed by Rabbi David Cohen, in the Old City. A resident of the capital's Neveh Ya'acov neighborhood has noticed a marked rise in the number of places in the yeshiva world that offer Kabbala. "When I first began learning Kabbala seven years ago there were about four different places I could choose from," he says. "Today there are dozens of places." The study of Kabbala is also spreading outside Jerusalem - most notably in Bnei Brak, the other center of haredi life and learning in Israel. For other signs that Kabbala is making inroads in the haredi community, one need only step into Yerid Hasefarim, a popular book store in the heart of Geula, where an entire wall is dedicated to kabbalistic books. "A few years ago it was difficult to get hold of books on Kabbala," says Shimon, a haredi student of Kabbala. "But today, just walk into a book store and you can find almost anything." At nehora.com - the haredi amazon.com - one can find new editions of Kabbala classics such as Rabbi Yehuda Petaya's Beit Lehem Yehuda, or Rabbi Haim Vital's Sefer Hagilgulim, which explicates in great detail how the transmigration of souls works. There are even copies of Sefer Hagilgulim in English. Rabbi Shmuel Eliyahu, chief rabbi of Safed, says demand for his grandfather Salman's book on Kabbala, called Kerem Shlomo, is growing exponentially. "It used to be that every 10 years or so we had to do another printing. Now we make a new printing a few times a year." Not long ago Otzrot Haim, the most basic beginner's manual on Lurianic Kabbala, could be found in three editions. Today, six new editions have appeared, each with its own unique running commentary and explanatory charts. Rabbi Yitzhak Tzror, a teacher of Kabbala from Yeshivat Sha'ar Hashamayim who edited one of these new editions of Otzrot Haim, has taken upon himself the task of teaching an introductory course in Kabbala to married yeshiva students. Over the past five years since he began, about 300 students have taken his one-year course, and he has sold 3,000 copies of his edition of Otzrot Haim. This year, one of Tzror's students is taking over the teaching of the basics while Tzror himself will be giving a more advanced course on a book called Sha'ar Hakavanot, which instructs in the use of heavenly intentions and meditations during prayer. WHAT HAS come over the conservative haredi community? Since the disastrous Shabbetai Zvi affair in the 17th century, which served as a powerful cautionary tale against the popular discussion of mystical concepts, the once-widespread study of Kabbala has been restricted to a select group of scholars. So what is causing the renewed interest in Kabbala in the haredi realm? There are several explanations. One is a dissatisfaction with Orthodoxy's overriding attention to the details of religious practice and the dry, legalistic approach to Torah study that excludes (for the most part) discussion of major theological issues such as reincarnation or the afterlife. Avraham, a student at the Ponevezh Yeshiva who says he is not personally drawn to Kabbala, admits that, for many of his fellow students, Kabbala quenches a thirst for deeper understanding. "In the generation after the Shoah the entire yeshiva world was enlisted to rehabilitate all that was destroyed. Emphasis was placed on the basics, Gemara and Halacha. Who pays when the ox gores the cow? What does the husband pay if he divorces his wife? But at some point people begin to feel the need for something more spiritual - food for the soul." Worship based almost solely on practice is not enough for many mature yeshiva students, who seek answers to questions about faith, providence, reward and punishment, etc. Many of those who want to have a deeper understanding of what it means to be a religious Jew are turning to Kabbala for those answers. Still, the question of why this is happening now, and in such great numbers, remains. Rabbi Meir Faivelson, who teaches Jewish philosophy and Kabbala at Yeshivat Derech Hashem in Jerusalem's Har Nof neighborhood, believes that Lithuanian haredi Judaism has undergone a transformation over the last decade or so that has made possible the integration of Kabbala. In contrast to the Enlightenment era or the aftermath of World War II, he notes, haredi Orthodoxy is no longer fighting for its very existence. "In previous generations faith-searching was discouraged for fear people would stray from the flock," explains Faivelson. "Today there is a realization that there is a lack of depth in issues of faith. Educators are also more confident that a little bit of spiritual searching can't hurt." Micha Odenheimer, a writer and Orthodox rabbi, thinks the trend is tied to a wider postmodern trend. "I think it is part of a general disappointment with rationalism," he says. "In the aftermath of World War II people began to understand that science is a double-edged sword. Not only can it be misused, it can err and it can fail to explain many phenomena. People began to realize science cannot solve all our problems. "On this backdrop," Odenheimer continues, "mysticism made a comeback. Mysticism goes beyond ideologies and tries to give a direct experience of the divine. This trend has made its way into the yeshiva world." Then there is the explanation of Rabbi Shmuel Eliyahu - a more mystical explanation that is tied to a larger, inexorable process of redemption that is drawing nearer. "People sense instinctively that the messianic era is drawing nearer," he says. "Learning Kabbala is a way of preparing one's soul for this era." BY NO means is devotion to Kabbala an easy thing in the haredi world. While more conventional yeshiva students strive to master Talmud and Jewish law, a type of knowledge that can be measured and tested - and used to gain respect and status in the yeshiva world - the mystic is often unappreciated and lacks the prestige and respect of a conventional rabbi because much of the kabbalist's intuitive, spiritually-focused knowledge is nearly impossible to convey to the uninitiated. Spending years meditating on holy names and learning divine intentions may add a profound mystical dimension to the performance of everyday mitzvot such as the wearing of tefillin, the hanging of a mezuza on a doorpost or performing a circumcision. But Kabbala is not the path chosen by the ambitious yeshiva student hoping to become a community rabbi, a rabbinic judge or a teacher in a yeshiva. Rather, it is pursued by the haredi who strives to reach new spiritual pinnacles in a selfless path to serving God. Moreover, the kabbalist's daily schedule is dictated by spiritual considerations. Kabbalists begin their day of study in the early morning hours. Why? The Zohar (the "Book of Splendor," a mystical commentary on the Torah often attributed to Rabbi Shimon Bar-Yohai, of the 2nd century C.E.) states that the second half of the evening, from midnight until daybreak, is particularly expedient for the study of Kabbala, as it is a time when God "entertains Himself with the righteous in the Garden of Eden." Kabbalists believe that during this part of the night, the mind grasps ideas incomprehensible at any other time. IT'S JUST after 5 a.m. at the Nahar Shalom Yeshiva. After completing Tikkun Hatzot, a special prayer and study session for the middle of the night that includes the mourning of the destruction of the Temple and the study of Kabbala, the students make their way through the dark streets of Jerusalem's Nahlaot neighborhood to the mikve to purify themselves before morning prayers. When prayers begin back at the yeshiva, there are at first no perceivable differences between this kabbalistic prayer group and its conventional counterparts. But then the supplicants reach the blessing before the recitation of psalms, and there is a hush. The man leading the prayer, who stands on a raised platform in the middle of the room in accordance with Sephardi tradition, consults a prayer book containing ineffable holy names and a complicated series of celestial intentions. These names and intentions are the focus of the supplicants' attention. Silently they read and meditate, turning page after page of what appear to the untrained eye to be nonsensical configurations of letters. After the blessing the prayer group recites the psalms normally. But once again they revert to the names and intentions for the final blessing after the psalms, which is recited by a man with white hair and piercing blue-green eyes, who takes over. The silent Amida prayer, the centerpiece of morning worship, takes over 20 minutes, instead of the normal six to eight minutes. Shrouded in their tallitot, the supplicants - many of whom have been awake all night - push their concentration to the limit as they pore over page after page of ineffable names and intentions. All that can be heard is the gentle swish of pages being turned. "The kabbalist who prays with mystical intentions is dealing with the nuts and bolts of celestial circuitry," says Rabbi Ezra Jacobs, a student of Kabbala at Sha'ar Hashamayim. "He is participating in the moving of spiritual energy." Rabbi Yitzchak Schwartz, a student of Kabbala for the past 18 years, says that after years of study and training, the act of prayer, which for many conventional Jews is not even a religious experience, is transformed by the kabbalist into a mystical union with the upper worlds that has far-reaching spiritual ramifications. "An authentic kabbalist is a channel for spiritual energies," says Schwartz. "The more competent he is, the more the flow of holiness comes through, bringing abundance into the world. This current elevates him as well." NOT EVERYONE is satisfied with the abstract, meditative nature of Lurianic Kabbala, in which endless inquiries are made to resolve apparent contradictions in the texts between various amorphous concepts, but no attempt is made to interpret or translate these terms into material ideas that can be understood by the layman. Many students of Kabbala want to translate their intuitive knowledge into teachings that help themselves and others better understand everyday human experiences. Rabbi David Aaron, a former yeshiva student who learned with Rabbi Shlomo Fisher, head of Yeshivat Itri, says he studied Kabbala for over a decade before he had a real breakthrough. "For a while I thought I was learning physics or chemistry. It was all so technical," says Aaron, a popular lecturer and author of eight books on Kabbala for a general audience, including The Secret Life of God. "I understood what I was reading in Etz Hahayim - all the heavenly emanations and their interrelations, etc., but I did not understand how it was applicable to my life." According to Rabbi Faivelson, concepts used by the Arizal are seen as allegories that must be decoded to understand an underlying message: "The idea is to reach a deeper understanding of how God runs the world and what our purpose is on earth." Kabbalists believe these allegories were not arbitrarily chosen to explain the underlying concepts. Rather, "kabbalistic allegory is an expression of pictures and images through which the ways of God's providence were revealed to the prophets," wrote Rabbi Haim Friedlander, a former spiritual counselor in the Ponevezh Yeshiva who passed away over a decade ago. "The ways of God's providence cannot be revealed directly," he wrote. "Instead, they are reflected by images and pictures imprinted on the prophet's soul. The prophet 'sees' these images in a spiritual, not material, sense. At the same time, the prophet understands that these images are just an allegory for God's glory." For some, these allegories, inspired by God, are essential in their own right to the mystical process of coming closer to God. This reflects the abstract style of Jewish mysticism that the yeshiva world calls "Sephardi" Kabbala, after the mystical tradition developed by Jews in Eastern countries. However, despite its name, many Ashkenazi Jews have adopted this style. By contrast, "Ashkenazi" Kabbala attempts to give rational interpretations to the abstract kabbalistic concepts to make them applicable to everyday religious life; in the case of the allegories, the translation of these images is important as an aid in serving God out of a deeper understanding of His ways. Equally a misnomer, the study of "Ashkenazi" Kabbala is not restricted to Ashkenazi Jews. In fact, the single most important "Ashkenazi" Kabbala thinker was Rabbi Moshe Haim Luzzatto - a Sephardi Jew of the 18th century. More than any other scholar, Luzzatto applied a systematic method of interpretation to Kabbala. His books were adopted enthusiastically by the Vilna Gaon, and in the post-Holocaust era, Ponevezh's Friedlander reprinted Luzzatto's books, single-handedly setting in motion a Luzzatto renaissance. An outstanding result of this renaissance is Rabbi Moshe Shapira, head of the Shem Shmatata Kollel. Through men like Shapira, kabbalistic thought and terminology have made their way into the elite intellectual circles of the haredi yeshiva world. Shapira, one of the most respected lecturers on Jewish philosophy in the Lithuanian haredi yeshiva world, gives dozens of classes weekly - some open to the general public, others offered to a select few. Shapira's weekly class in Jerusalem's Ramat Shlomo neighborhood is regularly packed to full capacity and beyond. "Rabbi Shapira is trendy among the really intellectual Lithuanians," says Avraham, a veteran student at Ponevezh. "Shapira uses kabbalistic thought and texts to bring depth to the ideas he teaches." The very fact that Shapira - who is emulated by hundreds of serious young yeshiva students - learns Kabbala could give a push to Kabbala's popularity in the mainstream haredi world. Still, in Lithuanian yeshivot students are not encouraged to delve into the mystical. Yeshiva students who turn to Kabbala do so secretly. "If someone says 'I am learning Kabbala' it is considered hubris," says Ya'acov Schlaff, administrative head of Yeshivat Sha'ar Hashamayim. "It's as if the guy is saying, 'I've already finished the entire Talmud with all the commentaries and now I am ready for Kabbala.' Who can honestly say that?" Most of the haredi yeshiva students studying Kabbala these days have already spent many years mastering the basics, says Tzror, Sha'ar Hashamayim's Kabbala teacher - and they continue to supplement their Kabbala studies with Talmud and Halacha. "You cannot have a very deep understanding of Kabbala unless you know how to learn Gemara," notes Tzror. Nevertheless, he is convinced that knowledge of Kabbala is essential to reaching spiritual perfection. That's why he sees nothing wrong with teaching young married men under the age of 40 (against the age-old prohibition) who have a strong background in Gemara. "How can it be that someone truly worships God without knowing the innermost meaning of the Torah?" asks Tzror, although he admits that heads of many yeshivot are wary of his Kabbala crash course. "The main fear is that these young men will abandon conventional learning. I admit that is a real danger," he says. "But I believe it is enough to devote an hour a week. If I could convince people of that much, it would be a tremendous thing." NAHAR SHALOM, 6:30 a.m. The man leading prayers begins the repetition of the Amida prayer. "Blessed are You God...," he pauses to scan page after page of holy names and meditations. He is elevating his prayers - and those of the entire congregation - to the highest supernal levels, striving for God's throne. He is the messenger of those who have gathered before daybreak to praise their Lord and who wait now in silent expectation: If this man, chosen for his holiness, has the proper concentration, pureness of thoughts and perfection of personal traits, perhaps his prayer and the prayers of all those present will influence the celestial world. Perhaps they will bring spiritual and physical abundance to this world. They will never know for sure, however. Prayer is over, and the anticlimax is almost palpable. "See you tomorrow," a dark rotund man with a gravelly voice says to a fellow supplicant. "Yeah," comes the reply. "Tomorrow."