The theory of correlation finds its origins in the pioneering work of Francis Galton. Lark Pearson and R. A. Fisher did much to develop the foundations of the subject in the early part of the twentieth century as the theory of mathematical statistics and its applications took shape. This book dates back to the 1930s, meeting the requirements of the time by providing tables of correlation coefficients to a considerable degree of accuracy, whilst also discussing a number of illustrative examples that employ the tables to provide a guide in drawing inference from observation.