Sir William Bate Hardy (1864–1934) was a celebrated British biologist and member of the Royal Society, whose scientific aims were summarized by Sir Hugh Anderson in the following terms: 'Hardy once observed a cell divide under a microscope, and wondered why.' This book contains his 59 scientific papers on a variety of subjects, reflective of his interdisciplinary attitude to scientific topics, written between 1891 and 1933. This volume will be of value to anyone with an interest in Hardy's academic career and legacy.