Until relatively recently, Israel’s tourist-packed Dead Sea was rarely visited and difficult to find without a native guide.Nevertheless, intrigued by the biblical account of the destruction of Sodom and by rumors of the lake’s uncommon properties, several intrepid travelers did make the journey over the years, mostly in the 19th century. Some even lived to tell the tale.The Jordan River, which feeds the Dead Sea and figures prominently in Hebrew and Christian scriptures, was easier for the curious to locate and study without worry from the Dead Sea’s hostile dangers of money-grubbing nomads, impossible heat, toxic wildlife and treacherous terrain.Barbara Kreiger’s The Dead Sea and the Jordan River chronicles the natural and human history of these increasingly troubled waters, including accounts by travelers, pilgrims and explorers attracted to the area by religious, adventurous, scientific, political or economic motivations.Among the better-known visitors were Herman Melville and Mark Twain (Twain described the Dead Sea as “a funny bath”).The fast-shrinking, sewage-tainted Jordan River takes a meandering 210 km. to cover a linear distance of 105 km. between Lake Kinneret (the Sea of Galilee) and the Dead Sea. Its ever-downward path, which early explorers had great difficulty mapping, drops approximately 90 centimeters per kilometer.At its terminus lies the Dead Sea (really a lake) just 32 kilometers from Jerusalem but 1,220 meters lower in altitude. It is much more solid than Utah’s Great Salt Lake and much more saline than the Mediterranean. Its famous mineral content – magnesium chloride, sodium chloride, calcium chloride, potassium chloride and magnesium bromide – spells big business on both the Israeli and Jordanian shores.Kreiger relates that the first European known to have traveled completely around the Dead Sea was the German naturalist and physician Ulrich Jasper Seetzen in 1806. He sent a 50-page summary of his findings, including a critically important hand-drawn map, to the Palestine Association in London. In 1835, Christopher Costigan from Ireland was the first modern traveler to sail on the lake, though he suffered endless misadventures and subsequently died of what was probably malaria.Despite its English moniker, the Dead Sea long harbored some interesting algae and bacteria, though years of drought starting in 1981 mostly wiped out these microorganisms due to the rising salt concentration of the lake, writes Kreiger.However, even if virtually nothing can live in its waters, the Dead Sea possesses unique healthful qualities that have been quantified and analyzed for their medical benefits. The minerals and their vapors ease respiratory and digestive problems, while the salty water and the unusually filtered sunlight at this lowest spot on Earth alleviate skin conditions such as psoriasis.The salutary effects of the lake and its feeder mineral springs have been noted since antiquity, according to the author.“There is, for example, archeological evidence of a kind of health resort on the southwest side near Ein Bokek, which is thought to have been popular in the Herodian period.”The vast Dead Sea Works, which extracts minerals including potash for agricultural use, was founded by the Russian immigrant Moshe Novomeysky. It took him many torturous years to get the project going, having first approached the Turks for permission to extract salts from the Dead Sea in 1907 and then submitting a formal application to the British in 1920.Due to political instability, bureaucratic red tape and British anti-Semitism, Novomeysky won approval only in 1929. By 1947, the Dead Sea Works’ north and south plants were mining 100,000 tons of potash per year and providing a livelihood to at least 10,000 Jews and Arabs.The War of Independence brought things to a halt, and the company was nationalized (and nearly folded) in the 1950s before making a successful comeback.The Arab Potash Company was set up on the Jordanian side of the Dead Sea in 1956.The vast amount of mineral extraction, exacerbated by the diversion of much of the Jordan’s flow for irrigation purposes (not to mention stressers including tourism and climate change), has drastically altered and depleted the Dead Sea and caused dangerous sinkholes in its vicinity.What used to be the lake’s southern basin is today “a large artificial pool” that threatens to flood the hotels. Channels, dams, pumping stations and Med-Dead and Red-Dead canals were among solutions tried or shelved over the years.The Jordan and the Dead Sea are two halves of “an environmental tragedy,” writes Kreiger. Naturally, politics are muddying the waters as well. To her credit, for the most part (aside from a jab at “the occupation,” for instance) the author remains a neutral reporter.Will these iconic waterways survive much longer? Kreiger vacillates between optimism and pessimism because it all depends on the swift implementation of wise trilateral policies by Israel, Jordan and the Palestinian Authority. We can only hope.