When Robin Cook wrote Coma in 1977, the idea of hospital patients being incubated for their vital organs sounded like science fiction. Twenty years later, this gripping thriller about a thriving international black market in human hearts, livers and kidneys could come from tomorrow's "Nightline." Author Gerritsen was an internist before she switched her energies to writing, and her experience shows in every scene. When young surgical resident Dr. Abby DiMatteo assists at her first "harvest" (the removal of living organs from a patient declared legally brain dead) at Boston's posh Bayside Hospital, "she felt vaguely nauseated by the whine of the blade, the smell of bone dust," neither of which seem to bother the veterans. It's obviously a personal memory being mined for good fictional purposes.