A mammoth documentary with special flavor and importance, this semi-official study puts together the political sociology of Detroit, based on profiles of five ""multi-problem"" families, in an effort to discover what triggered the 1967 riots. The black Stallings and Mirow families came from the South; Lentick the Cornish miner, Jensen the Swedish logger, and the Hungarian Norveth met on the line that formed in 1919 when Ford announced the $5 a day wage scale. We learn with dismay that virtually no aspect of these families' lives has not been recorded by official agencies; and something deeper than dismay emerges when Conot pinpoints the boombust cycle of manufacturing as the key to family instability and generation-to-generation despair. The destitution of the 1930's, when Ford hired black workers at $1 a day, was preceded and followed by grim Detroit living conditions, and Conot concludes that the nation's most intensive, acronym-crammed poverty programs ""never reached the hard core."" As the first Stallings' grandson Brett stands in court sentenced to life imprisonment for murder, Conot sees ""the end of an era."" He has little positive vision of the next. But this is one of the most perceptive urban studies ever written.