Hermann Joseph Muller (1890-1967) was a member of the early genetics group at Columbia University that developed the chromosome theory of inheritance. T. H. Morgan received the Nobel Prize in Medicine and Physiology for this work in 1934, and Muller, his student, received the Nobel Prize in 1946 for his discovery of radiation-induced mutation. The Modern Concept of Nature: Essays on Theoretical Biology by H. J. Muller, deals with Muller's major contributions to the theory of the gene, the induction of mutations, the principles of genetic load, and the neo-Darwinian theory of evolution. These essays contributed to the modern outlook of biology, and they are important to the historian and the biologist who wish to trace the evolution of scientific concepts or to read, first hand, the papers which laid the basis for the major portion of our genetic knowledge. Muller's writings extended beyond contributions to technical journals. He was an active critic of social abuse of science; he advocated eugenic programs based on free choice; and he played a major role in the reform of high school biology. Muller's social views were published in magazines and journals which are accessible to scholars more than to the lay reader or student. They have been collected in a companion volume, Man's Future Birthright: Essays in Science and Humanity by H. J. Muller, also published by State University of New York Press, to show how extensively he thought our lives are affected by radiation, evolution, modern medicine, and gene theory. He attempted to alert humanity to the dangers of neglect and abuse of their genetic heritage. He also used humanistic values to urge mankind to improve itself, to foster cooperativeness, to increase health and intelligence, and to adopt an evolutionary outlook. The relation of science to values is often neglected because of the inaccessibility of the written contributions of important scientists. To read Muller's major essays in these two areas is an important way to evaluate a scientist's career, his maturation of ideas, and his developing application of science to society.

genetics. " It is simply the appropriation of that term, very likely with insufficient knowledge and respect for its past usage. For that, the Editor alone is responsible and requests tolerance. He has, as far as he can tell, no intention or desire to use it for any historiographical purposes other than that just mentioned. Even more important, the decision to consider Muller together with Fisher, Haldane and Wright is also not original. Crow (1984) has already done so, arguing persua sively that Muller was "keenly interested in evolution and made sub stantial contributions to the development of the neo-Darwinian view. " Crow's reasons for considering these four figures together and the reasons discussed above are complementary. This book continues a historiographical choice he initiated; others will have to judge whether it is appropriate. The foregoing considerations were intended to show why Fisher, Haldane, Muller and Wright should be considered together in the history of theoretical evolutionary genetics. I By a welcome stroke of luck, from the point of view of the Editor, all four of these figures were born almost together, between 1889 and 1892, and almost exactly a century ago. It therefore seemed appropriate to use their birth cente naries to consider their work together. A conference was held at Boston University, on March 6, 1990, under the auspices of the Boston Center for the Philosophy and History of Science, to discuss their work. This book has emerged mainly from that conference.