"It is the great glory as it is the great threat of science that everything that is in principle possible can be done if the intention to do it is sufficiently resolute." This theme, from the title essay, runs throughout this new collection of Peter Medawar's writings. A passionate advocate of scientific endeavour, he wrote, lectured and reviewed widely, describing the glories of scientific achievement and warning of the dangers of pseudo-scientific deception. This selection, made posthumously from essays now unavailable elsewhere, and including some previously unpublished material, covers a characteristically wide range of subjects: genetics, evolution, creativity, philosophy, scientific fraud, and attitudes to death and the prolongation of life. Either as a companion to "Pluto's Republic" , the last selection of essays to be made before he died, or as an introduction to his writing, this volume should intrigue, stimulate, and delight. It is intended for moral philosophers, research biologists, geneticists, and other scientists, environmentalists, and the general reader.