Internship and junior residency with Dr. Bill Ryan at Manhattan's top teaching hospital--not much of a novel, perhaps (Ryan's romances are likely to leave you cold), but a compelling, exhausting, disturbing case-by-case workup which effectively captures the hospital M.D.'s sense of being put through the wringer. Not that Dr. Ravin heaps on the self-pity. To the contrary, he wisely plays up the comedy and everyday-ness of Ryan's ordeal: feuds with hospital officials (""Don't be so right,"" his roommate Arch advises); black-comic advice from seemingly callous resident Iggy (it was his job ""to inspire, protect, instruct and keep Ryan from killing his patients""); the don't-tell-me-about-it humor of hospital incompetence; the California-ized chatter of intern Biotto (""heavily into his patients as whole humans""); and Ryan's reluctant collaboration with an older doc on a paper (""Gordio: Another Cause of the Gay Bowel Syndrome""). So, against this easygoing, ironic background, the cases themselves sneak up on you with digging impact: emergency-room crises, arguments over a ""veggie"" whom lazy Biotto has allowed to die, complications in cardiology and neurology. And, above all, there are Ryan's two months in ""Cancer City,"" Whipple Hospital--""the only place where the Mets always win"" (Mets as in metastases); without sensationalism or sentimentality, Ravin bombards the reader with devastating vignettes of terminal patients and their families, with Ryan's bitter, sleepless exhaustion, with ""the smells, the dying, the heat."" Much less involving, however, is Ryan's love-life--his graduation from understandable one-night stands to simultaneous affairs with a sexy, married senior doctor and vulnerable nurse Hope Lo; here the prose slips into clichÃ‰s, Ryan slips into unconvincing naivetÃ‰, and a third quasi-romance with a terminally ill charmer is somehow cheapened. But if this never quite works, then, as a shapely narrative or a novel of character, the comedy/tragedy counterpoint is grittily on-the-mark: the medical-fiction audience will laugh, wince, and be glued to the page.