Sam Poole was only 17 when his parents discovered he had an irreversibly damaged heart--cardiomyopathy--and barely 18 when he became Stanford University's Heart Transplant No. 120. Between those two events lurked indecision, escalating illness, and the interminable wait for a suitable donor. But ""Mum"" Victoria manages to make the several Poole residences in Maine sound like such a gay picnic of a life--six naughty cherubs, a flighty sister, an ironclad husband who snarls manfully on cue--that it's difficult to believe that Sam could get much more than the sniffles. Still, the shoulder-squaring matriarch of the clan manages to shed plenty of tears coast-to-coast as she and her husband alternate tours of duty with Sam in California: she's in limbo for weeks on end, conscious that Sam's time is running out, missing the kids' Christmas shenanigans. And when the transplant finally comes about, tears are inescapable: Sam's worn-out heart falls apart in the removing doctor's hand. Sam has plenty of spunk: athletic rather than academic, he endures incredible agony to live normally again. Of course, ""normally"" is relative: he takes 50 medicinal doses a day, some to suppress the white blood ceils and some to counteract side effects; he can't play contact sports or return to his beloved rowing; he's had three heart rejections in as many years (successfully ""resolved""); and drugs have left him a virtual hemophiliac. If there were more of Sam and less cutesy background, the book would be far more effective. As it is, a mixed blessing.