SoLawrence Weschler was minding his own business, as all his storiesbegin, when he got a call from Gravity Goldberg. Gravity (her real name!) introduced herself as the Director of Public Programs and VisitorExperience at The Contemporary Jewish Museum in San Francisco. She wascalling, she told him, to apprise him of an upcoming show--an inauguralexhibition, that is, of a recently uncovered trove of work by ShimmelZohar, a mid-19th-century Lithuanian immigrant photographer(contemporary of Mathew Brady), who had chronicled the Jewish immigrantcommunity of the Lower East Side of 1860s-1870s Manhattan inunparalleled detail, compiling a complete inventory of professions andtypes. Or not. There was, she suggested, some slippage in the wholestory, and they were trying to find someone who might be willing toinvestigate things, and they were wondering, might he be interested? Thusbegins an antic tale of investigative perplex and vertiginous inquiry,as Weschler tracks down Stephen Berkman, the wet-collodion devotee whoclaims to have discovered the trove in question, but it's a long andloopy story. And indeed, Weschler's account evolves into the fourthvolume of his ongoing "Chronicles of Slippage" series, doing for theearly history of photography and the long heritance of Judaism what theseries' first volume, the Pulitzer-shortlisted Mr. Wilson's Cabinet of Wonder, once did for the history of museums and the phenomenology of marvel. Andthat's just the half of it, for the main text sprouts a veritabledelirium of digressive footnotes (taking up more than half the book),constituting what may be the closest we are going to ever get by way ofmemoir from this confounding and beloved writer.