Two men with failing hearts become candidates for transplants and wait with their wives for replacements--in this latest didactic novel from the ever-prolific Denker. Fans of the long-running Reader's Digest series about talking body parts ("I Am Joe's Hypothalamus," etc.) will find themselves humming along here as a busy midwestern cardiologist, Allen McCandless, treats the cardiomyopathic hearts of two men--one rich, one of modest circumstances, one with Admiral Poindexter's old job at the National Security Agency, one a simple tree-surgeon, one unhappily married, one with a good wife and two children, one in the twilight of life, one in the prime of life, one in the. . .well, you get the picture. The irony of it all, though, is that these two men--one so important and one just your average joe--are both the same size and shape and blood type, so they need The Same Heart. Dr. McCandless is getting much pressure from the crass, unmedically trained hospital administrator to make sure that the next available heart goes to the Washington bigwig, so that the hospital will get lots of publicity. But Dr. McCandless, who would be able to date the attractive wile of the National Security Director after his death, is not swayed by earthly pressures. He will do the Right Thing. . . For medical-drama fans and heart patients with strong stomachs.