John Burdon Sanderson Haldane was a giant among men. He made major contributions to genetics, population biology, and evolutionary theory. He was at once comfortable in mathematics, chemistry, microbiology and animal physiology. But it was his belief in education that led to his preparing his popular essays for publication. In his own words: "Many scientific workers believe that they should confine their publications to learned journals. I think that the public has a right to know what is going on inside the laboratories, for some of which it pays." So begins Haldane's collection of essays, perhaps the most public intellectual communicating science before the writings of Stephen Jay Gould. The first part of the volume emphasizes the important developments in biology and natural science in the first quarter of the century. As such, it provides a benchmark for studies of the next three quarters of the century. In an unusual introduction, Price takes the readers through their paces, discussing the situation then and now in vitamins, oxygen want, disease controls, and the rewards of science as such. This is followed by Haldane's views on society, art, religion and economy as seen through the eyes of a politically alert major scientist. The editor provides readers unfamiliar with Haldane with a carefully rendered chronology of a life that began in 1892 and that spanned much of the present century. Despite ideas on race, class and politics that have seen better times, Haldane was truly exceptional in translating the science of his time into ideas that "everyman" could readily grasp. His predictions on what science would achieve were on target far more often than not. But even his failed predictions are perhaps the most interesting of all. They throw into sharp relief the truly novel and revolutionary developments in science over the past 75 years. J.B.S. Haldane held many positions and received many honors during his lifetime. But for most of the period covered in this volume, he was the William Dunn Reader in Biochemistry at Cambridge University. He simultaneously served as Fellow of New College, in Oxford University's Horticultural Institute. Carl A. Price served until 1999 as professor IIof plant molecular biology in the Waksman Institute of Microbiology at Rutgers, the State University of New Jersey. He also served as the editor of Plant Molecular Biology Reporter from 1983 until 1997. This is the first volume in a new series on the history and theory of science.