Deadheads will form the initial queue for this startlingly good debut, a road book that follows a boarding-school dropout -- turned -- Ecstasy dealer who intermittently joins the movable feast that trailed Jerry Garcia & Co. in the late '80s. Ludington earns knowing laughs from critical quirks among the faithful (''Taking a piss during 'C.C. Rider' had become almost automatic for me... I would usually be standing at a urinal when Bobby's lugubrious, off-key attempt at a slide solo reached me muffled by a cinder-block wall''). And few writers have managed more clearheaded descriptions of getting high -- or coming down. But it'd be a shame if the words Dead and drugs scared off serious-lit types, who might otherwise marvel at Ludington's ferocious command of character and Americana.