Slackly plotted though occasionally spooky yarn about Boston- area ghosts--and the hardcover debut of psychic detective Ryerson Biergarten, whose cases Wright (Little Boy Lost, p. 498, etc.) has covered in several pseudonymous (``F.W. Armstrong'') paperbacks. Many of Wright's novels have imagined a twilight zone between life and death in which ghosts wander, not sure whether they're dead or alive, and into which the living may stumble. Here, this zone and its denizens are ill-defined, presented in a sometimes nearly inchoate shuffle of scenes: One ghost, a woman who inexplicably can widen her mouth to an ``impossible'' length, picks up men and takes them to deserted rooms where she reads them bad horror novels; another ghost, a woman kidnapped through a psychic ``gateway'' into the world of the dead, enjoys standing by the ocean; and yet another, that of a 90-year-old clockmaker, only curses: ``Eat my shorts!'' Among the dizzying vignettes is stitched the story of Sam Goodlow, a hit-and-run murder victim who appears (as a man; a boy; a transparent man with internal organs showing) to Biergarten--who, other than for his psychic powers, is such a colorless character that he might be a ghost himself. Through talks with Goodlow (```Dammit, I can see through your head,' Ryerson said'') plus some standard gumshoeing, Ryerson learns that Goodlow was killed as part of a plot in which a rich old woman was murdered by her doppelgÑnger in order to steal the woman's estate. The climax finds the doppelgÑnger's ghost aiming a gun at Ryerson's body while the detective's spirit--which has left his body due to a previous wound--watches. Justice prevails, but Ryerson wakes up with a terrible headache. The entire novel's a bit ghostly itself: eerie, but so thin you can see right through it.