Dr. Dietrich is examining the life of one of the most controversial and enigmatic figures in twentieth century biology, Richard B. Goldschmidt. Known now for his heretical denial of gradual evolution and the existence of the gene, in his time Goldschmidt was controversial but recognized as one of the top biologists in Germany and later in the United States. Dr. Dietrich is examining the development of Goldschmidt's scientific thought, the impact of his forced immigration to a radically different institutional setting in the United States, and the creation and perpetuation of his status as a heretic. This project promises to contribute significantly to the history of biology in the twentieth century by clarifying important issues concerning styles of scientific practice, the dynamics of scientific controversy, and the uses of history in scientific rhetoric.