This volume is a collection of papers assembled to honor Hiroya Kawanabe, an eminent Japanese ecologist who studied fishes and other organisms. Kawanabe retired from his position as Professor at Kyoto University in March 1996. In the first section of the volume his career is highlighted by a biography describing his life and work, a bibliography of his more than 750 lifetime publications, and a personal interview with a colleague who has been close to his work throughout his career. Papers in the second section of the volume include invited reviews of research on fish ecology in Japan, a historical overview of freshwater fishes of Japan, and recent studies on sex change among reef fishes. The 24 papers in the third section of the volume by Japanese fish biologists and their collaborators cover a wide variety of topics on fish biology. These include papers on evolution, genetics, systematics, reproductive biology, early life history, life history variation, behavior, physiology, ecology, and zoogeography. These papers address fishes from lentic, lotic, and marine ecosystems in Japan, Asia, Africa, North America, and in some cases worldwide. One of Hiroya Kawanabe’s most brilliant and lasting contributions was to foster collaboration between Japanese ecologists and other scientists.