Fritz Muller (1821-1897), though not as well known as his colleague Charles Darwin, belongs in the cohort of great nineteenth-century naturalists. Recovering Muller's legacy, David A. West describes the close intellectual kinship between Muller and Darwin and details a lively correspondence that spanned seventeen years. The two scientists, despite living on separate continents, often discussed new research topics and exchanged groundbreaking ideas that unequivocally moved the field of evolutionary biology forward. Muller was unique among naturalists testing Darwin's theory of natural...