In flesh, and as portrayed in Jack Kerouac's novels On the Road (as Dean Moriarty) and Big Sur (as Cody Pomeroy), Neal Cassady embodied the zeitgeist of his generation, among whom was the author, his wife of 15 chaotic years. He was 22, three years her junior, when she married Cassady in 1948 and became handmaiden to a passionately devoted brotherhood: her husband, her extramarital lover Kerouac and Allen Ginsberg, all, as Kerouc put it, `` . . . in the car heading for the world unknown.'' So hazardous proved the terrain that Cassady died at age 43; Kerouac the following year, at 47. Of the famed Beat trio, only Ginsberg would claim his place as elder statesman, his survivorship forecast in his letters to Cassady: ``It ain't right to take on so paranoiac just to challenge and see how far you can go''; ``I feel so evil when I not agree in blindness.'' How hard Cassady, possessed of ``humid magnetism'' and ``dangerous glamour,'' traveled is a tale of self-destruction recreated with felt tragedy by a wife who yearned for conventional family life, to raise their three children in suburban security on the San Francisco peninsula, to be assured that her railway brakeman husband would bring home a weekly paycheck. But compulsive infidelity, drugs, spells in prison, horse-race gambling and the road kept the well-intentioned Cassady otherwise engaged. Among legendary Beats who pass through these memoirs are Gary Snyder, Lawrence Ferlinghetti, Philip Whalen, Michael McClure, along with others who left an indelible impress on the lives of the Cassadys: Ken Kesey and the Merry Pranksters, an astrologer, a cult of clairvoyants. To the familiar history of the Beat Generation, Carolyn Cassady adds a proprietary chapter marked with newness, self-exposure, love and poignancy. Photos not seen by PW . (July) .