From an objective and scientific standpoint, Dr. Mellanby examines the problems of pollution of air, land, river, and the sea, by herbicides, pesticides, sewage, industrial effluents, gases, radiation, leakages, over-drainage, mistakes and mismanagement, in Britain to-day. He sets out to placate neither farmers nor naturalists, but to explain in each case what is happening, to point to both dangers and practical necessities, and to discuss what steps should be taken. Dr. Mellanby is Director of the Nature Conservancy's Monks Wood Experimental Station, was head of the Entomology department at Rothamsted, and for many years before that did research in medical entomology both in Britain and the tropics.