Scientific observation, motivated by affections and a sense of man's kinship with other living creatures are equal components of the selections in this well-conceived and executed anthology. In an introduction, of necessity longer than most, Mr. Krutch traces the course of nature writing from the Middle Ages to Thoreau, in whom he finds the first and greatest American spokesman of this genre. The thirty two selections are grouped under subject heading, to each of which Mr. Krutch contributes a brief preface binding them together in major interest. Among the contributors, in addition of course to Thoreau, are numbered Gustav Eckstein, Mark Twain, Henry Boston, William Beebe, and others. There's a selection from Mr. Krutch's own Twelve Seasans. Will Cuppy's bit from How to Become Extinct is very amusing; there's an absorbing extract from Byrd's Alone. Teale's Natural History in Times Square is an eye opener. On the whole the selections are written with warmth and charm, and are unobtrusively informative.