It was just over a century ago that the first stirrings began which led eventually to the separation of psychology from the parent stem of philosophy. To understand and to evaluate properly the work that psychologists are doing today one must understand the main outlines of the developments which have transformed a largely abstract philosophical study pursued by a small number of individuals into an independent, if rudimentary, science with many practical applications. The aim of this book is to trace the development of psychology in Great Britain from the middle of the nineteenth century to the time of the Second World War, during which period this transformation took place.