She won't die, Ellie Simon's mother has promised her. Just what's wrong with her patent ductus arteriosus, she knows. But even with the finest preparation, the sanest, most sympathetic parents, being in the hospital for heart surgery is tough--and a sense of humor is the best defense. ""'Urine analysis,' a jolly voice said"" . . . and Ellie launches into an account of the embarrassment of bedpans (especially when ""nothing happens""), the awfulness of some kids' mothers (boy roommate Kevin's ""gets nervous,"" he says, ""if she doesn't have anything to be concerned about""), the pluses and minuses of various doctors, and such side issues as race (to bouncy fellow-patient Sonia, who questions Ellie's disbelief in God: ""Being Jewish is more like being black than like being Baptist""). She rebels at the prospect of a catheterization that she wasn't warned about and can't escape depression at the constant talk of death. Thinking about her scar-to-be, she's sorry for herself; then ashamed because Theresa, who has sickle cell anemia, ""won't live until she's eighty,"" scar or not: ""And she knows it."" It's sharp, fast, funny, genuinely serious, and helpfully informative--a tonic for older kids as potent as Curious George's confinement for smaller fry.