DENNIS MCNALLY graduated from St. Lawrence University in Canton, New York, and received a Ph.D. in American history from the University of Massachusetts. After being selected as the Grateful Dead's official historian in 1980, he assumed the band's publicity duties in 1984 and has been running that post ever since. He is the author of one previous book, "Desolate Angel: Jack Kerouac, the Beat Generation, and America," He lives with his wife in San Francisco.