When one-time Talmudic scholar and ex-CIA cryptanalyst Paul Nomberg takes a crack at deciphering the Ullman diary, he has no idea what he's getting himself into. Asher Ullman, a doctor in the crematorium of a Polish concentration camp, was planning an uprising of the workers when he was evidently betrayed by a member of his own revolutionary committee -- someone who reportedly now holds an important position in the Israeli government. The coded -- perhaps in chess language -- diary indicates the location of a time capsule which contains the name of the informer. Nomberg takes the assignment even though he doesn't know which of his two employers -- Aaron Smilansky or Mayanna Tamir -- is actually working for Israeli Internal Security (Shin Beth). The mathematically minded New Yorker confesses he has ""no interest in causes"" when he first arrives at the Nazi archives in Jerusalem. After meeting with assorted camp survivors, the decoder realizes he doesn't know ""what or who"" he's supposed to be tracking down -- whether it's a perfidious Jew or a cache of valuables from the Nazi plunder which Ullman intended to return to the camp victims' heirs. The befuddled cryptologist is ""drifting in a fog of doubts"" until Mayanna, moonlighting from Shin Beth and desperate, admits that a fortune in diamonds does exist. Nomberg somehow breaks the code (an easy tangram); however, he's so disenchanted with it all -- fed up with ""the word game he was playing with a dead man. . ."" -- that he resolves the treasure should stay buried. An admirably interwoven teaser -- in fact you might need a computer -- but you almost have to read on.