DOCTOR SAX (245 pp.)Jack Kerouac Grove Press (clothbound, $3.50; paperback, $1.75).
The decade's most celebrated banger of mystical ashcans has written a fictional account of his childhood, and surprisingly, while the lad he describes is no Penrod, neither is he Little Boy Beat. Jack Duluoz, the author's alter-Kerouac, is exuberantly profane and comfortably delinquenta kind of city-bound Tom Sawyer who at one point seems ready to go rafting down New England's flood-swollen Merrimack River on a henhouse roof.
But like Sawyer, young Duluoz is a fair-weather rebel, and he generally rambles home in...