All about all kinds of swans and something more--an intimate appreciation of their nature, informed recognition of efforts to sustain them. Starting with the Philadelphia Zoological Garden's first successful attempt to breed Trumpeters in captivity, told in day-to-day detail, Mr. McAvoy passes on to a broad description of the characteristics and behavior of swans generally, not only translating scientific terms into ordinary language but also explaining their significance. In along chapter devoted to swans as ""legend and inspiration,"" he recounts such diverse stories as the origin of the constellation Cygnus the Swan and Howard Pyle's The Swan Maiden The balance of the book consists of a chapter devoted to each type, frequently extended by first-hand observation, sometimes--especially in the case Of the ceremonial Swan Upping (inspecting and marking) of British Mute Swans--by intriguing incidents. In one aside, the author remarks that an excellent government publication is out-of-print, symptomatic both of his informality and his involvement with his subject. For readers Who become involved also, he provides a subdivided reading list appropriately including fiction. Even if this weren't the only comprehensive juvenile on the swan, it would be an uncommonly interesting study, as fine in its way as the author's, previous Hunt for the Whooping Cranes.