Ernst Haeckel (1834-1919), who is best known for his embryological principle that ontogeny recapitulates phylogeny, contributed not only to embryology but also to zoology, ecology, evolutionary theory and its application to human beings, and monistic philosophy and its social engagement. Keiko Sato's Haeckel and the Fantasy of Evolution provides an overview of Haeckel's scientific and philosophical endeavor as a whole, paying particular attention to his monistic philosophy and its nineteenth-century German context. It is a remarkable achievement for Japanese scholarship because, although there have been a couple of Japanese translations of Haeckel's writings, few book-length historical treatments in Japanese have been provided. Part 1 deals with sketching Haeckel's biographical information and the contents of his early masterpiece in zoology, Generelle Morphologie der Organismen (General Morphology of Organisms, 1866), thereby describing his route to monism. Chapter 1 presents Haeckel's early career in marine biology. In particular, Sato emphasizes the role played by the death of Anna Haeckel (née Sethe, 1835-64), Haeckel's first wife. This tragedy not only influenced the contents of Generelle Morphologie, which adopted evolutionary theory as the basis of biology, but also made Haeckel renounce his Protestant faith and commit himself to a monistic philosophy. Among the many monisms in the history of philosophy and science, Haeckel's took as real only one substance unifying body and soul, which was in turn governed by the sole law of substance.
