This comprehensive, up-to-date description of every conveivable variety of marsupial should satisfy the most avid interest. The only species native to North America, the opossum, is dealt with at length; the author debunks a recently held theory that they ""play dead"" because they are really scared into that state and, citing brain-wave research, indicates that they are playing as was originally believed. Possible theories about how most marsupials ended up in Australia (there are a few varieties in South America) are reviewed, based on the latest continental drift and fossil information. Beyond the basics about kangaroos found in most books, Jenkins includes such facts as that the mother produces a ""spare"" embryo held in reserve until survival of the first joey seems assured. The illustrations are excellent, though not every species is pictured. Because Australia houses the majority of marsupials, a chapter on their other unique animal family, the monotremes (platypus and echidna), is included. The extensive detail and care with which each variety is described makes this more advanced than most juveniles on the subject, and the suggested reading list is extensive. The author of Animals Without Parents (1970) and The Curious Mollusks (1972) has impressively dealt here with still another facet of the animal world.