This British import, by the author of the popular ""otter book,"" Ring of Bright Water (1961), takes on in a more formal, less expansive, fashion the incidence of seals and walruses in the world. In a solid reference book treatment Mr. Gavin reviews the thirty-odd Varieties of the sleek, intelligent sea mammals and each variety is covered by sections on distribution. population, appearance, habits, migration, reproduction, distribution, condition in captivity, and in sadly understated paragraphs, ""the species in relation to man."" ""Perhaps no other group of animals has suffered as much as the seals, their mass destruction involving a degree of horror and brutality that is without parallel,"" states Mr. Maxwell as he quietly puts down some misconceptions about the ""destructiveness"" of seals. There is also a straight-faced consideration of the myth of singing seals. Seals ""have no interest whatever in music."" Mebbe, but after contemplating the excellent photographs of the appealing little beasts in full cry, the reader may harbor a doubt. Fine popular reference book with seal-appeal.