Nature studies are usually too highly specialized, either in subject matter or in style, to appeal to very broad readership; but this book, subtitled ""A Natural History of the River"", is a triumphant exception to that general rule. In fact, in any attempt at assessment, one thinks inevitably of such writers as Thoreau and Maeterlinck. Mr. Bardach's material is nothing less than everything there is to be known about fresh waters, from their beginnings in glaciers, springs, and brooks, all their long way through lakes and rivers to the sea. He is especially interested in the structure of each ""community"" of plant and animal life at every stage, and his interest is not merely scientific--rather, it is an interest born of real love for his subject, of ""childlike"" wonder at the marvelous ingenuity of life, and of countless happy days spent by the sides of streams. The proper terminology for scientific fact is always supplied, but also shown is a fine consideration for the general reader's sensibilities; for example, how much more meaningful it is to be told that the space in a beaver's lodge is ""about equal to the inside of a Volkswagen,"" than to be given the exact number of cubic centimeters. The final third of the volume is a luminous account of all that rivers have meant to man and what he has done to them. This is, all told, a pleasurable and important book, one which everybody should enjoy.