As in The Year of the Koala (1975), Williamson merges fact and fiction as he follows the annual peregrinations of kangaroos--four species generally and several individuals especially--across the Australian landscape. The hybrid form of his report, which incorporates a year of detail into a narrative framework, is less awkward than one might expect (and lacks the syrup ladled on juveniles of this sort) but it's also less prepossessing than the varsity work of, say, Jane Goodall or George Schaller. Most people think of the kangaroo's upward mobility and endurance in parched conditions, and Williamson concurs, but a much fuller profile takes shape. The large kangaroos he surveyed--red, eastern gray, western gray, hill--travel in smallish, loosely bound groups, the females (like Wangarie here) and their joeys (two cm. at birth) in close contact for about eight months, then severing ties slowly, abruptly if circumstances intervene. By watching Wangarie, her progeny, and her group, Williamson reveals distinctive kangaroo biology: birth and (resident) infancy, dentition sequence along the jaw (sure indicators of age), evolutionary toe changes, urinary adaptation (concentrated, to avoid dehydration). And the month-by-month format allows behavioral patterns--seasonal feeding variations, mating rituals--to emerge and related issues (waterhole poison proposals, current research projects) to be introduced, without disturbing the story line. A good year for kangaroos, and a likable one.