Alfred Robb (1873–1936) was a British physicist who worked extensively in the area of special relativity. Originally published in 1936, this book essentially formed a second edition to Robb's A Theory of Time and Space (1914). The alteration in the title was made since it was thought the word 'geometry' better reflected the contents of the text. A considerable amount of fresh material was introduced for the second edition, with the introduction being rewritten and extended, whilst the proofs of a number of theorems were curtailed and simplified. This book will be of value to anyone with an interest in special relativity and the history of science.