In Dara Horn’s contemporary spin on the biblical Joseph story, it is sisters, not brothers, whose toxic rivalry leads to an Egyptian dungeon and devastating familial consequences.The main plot of this engrossing page-turner revolves around Josephine and Judith Ashkenazi. Even as children, Judith was so jealous of Josie’s superior intellect and looks that she had nearly let her younger sister die of an asthma attack. The adult Josie has channeled her brilliance into Genizah, an advanced social- media program that passively records and catalogues the details of users’ lives behind myriad virtual doors.As if Josie’s professional success weren’t maddening enough, the salt on Judith’s wounds is Josie’s sexy Israeli husband, Itamar, and their little girl, Tali, whose similarities to her aunt Judith make for a tense mother-daughter relationship.After Judith persuades Josie to accept a consulting job in Egypt – in the midst of the Arab Spring – Josie is kidnapped and presumed dead, allowing Judith to step into her sister’s shoes as surrogate wife and mother.Chained in a foreign prison, and blissfully sleeping in the arms of her brotherin- law, respectively, each sister undergoes a transformation in her understanding of the mechanisms of memory and free will. Each realizes that the past will forever haunt her as if it had been recorded with Genizah.“Nothing ever really disappears,” Josie says, “even when you want it to.” Yet each also realizes she possesses the power to change the past, and certainly the future, through her choices.Josie’s transformation is catalyzed by the only possession in her grim surroundings: a Hebrew-French copy of Maimonides’s 12th century opus Guide for the Perplexed. This famous philosophical work opens a window on the book’s two subplots, both of them historical fiction. One subplot imagines the dangerous and tense scenario in 12th-century Cairo that led Rabbi Moshe ben Maimon (Maimonides) to pen the anguished letter found hundreds of years later in the famous geniza (temporary storage for holy writings prior to proper burial) in the Fustat synagogue, describing his eight years of “disconsolate mourning” following the death at sea of his beloved brother David.The other subplot imagines the inner thoughts and feelings of Cambridge professor Solomon Schechter, the shtetl-born ilui (exceptional Talmud scholar) who managed to rescue hundreds of thousands of medieval documents (among them Maimonides’s letter and rough drafts of Guide for the Perplexed) from the Cairo geniza in 1896. Handling the ancient parchments terribly aggravates Schechter’s asthma, a condition affecting each of the book’s main characters in different ways.The National Jewish Book Award-winning author, who lives in New Jersey, explains in publicity materials for the book that her research revealed Schechter’s chronic asthma and Maimonides’s medical treatise on how to treat the lung condition.As the mother of three children with asthma, Horn was intrigued.“It was like a long chain of people who couldn’t breathe,” she relates. She therefore wove this theme into various layers of the narrative.At its heart, however, A Guide for the Perplexed is a Jewishly shaded exploration of the complexity of sibling relationships, an evergreen topic that Horn studies from the perspective of the Ashkenazi sisters, the Schechter twins and the ben Maimon brothers – as well as the twin “lady adventurers” Margaret Gibson and Agnes Lewis, whose initial discovery brought Schechter to Cairo. Of these pairs, only the Ashkenazi sisters are fictional.Jealousy, love, hatred, betrayal, manipulation, guilt, loyalty, forgiveness and redemption all have starring roles in this book that simultaneously explores the nexus of cutting-edge technology, memory and determinism.“Memory is the foundation of identity, but the way we become who we are isn’t through total recall,” Horn writes. “It’s by curating our memories – by choosing, out of that bottomless well of information what’s worth saving” – not unlike the vast Cairo geniza with its priceless manuscripts and useless receipts. With a Harvard PhD in Hebrew and Yiddish, and experience teaching Jewish literature and Israeli history, Horn names her characters with care. Josephine, of course, mirrors the original Joseph. Her sister Judith (Yael, rather than Yehudit, in Hebrew) bears names with more subtle connotations: the apocryphal maiden who beheads an Assyrian general, and the biblical gentile who drives a tent pin into the skull of the evil general Sisera. These women can be seen as brave heroines or bloodthirsty murderesses, depending on your viewpoint. Horn’s character evokes a similar ambivalence.It seems that Horn had some fun with some of the other names. For example, Itamar’s surname is Mizrahi as a foil to his wife’s Ashkenazi. And then there is Mosheh (she spells it with an ‘h’ at the end) in various permutations from the biblical savior of the Hebrew slaves to the scholar-physician Maimonides to little Musa, son of Josephine’s kidnapper – all residents of Egypt at one time or another.Suspense, humor, tragedy, history, technology, psychology – this book has them all. It’s a delightful read.