The purpose of this study is to present and examine significant British colonial theories on the advantages and disadvantages resulting to the mother country from the establishment and maintenance of overseas colonies. For what reasons was the building and preservation of Empire thought profitable or unprofitable to the British nation? Professor Knorr has performed a major service in providing a selection of representative statements in the course of a discussion which proceeds by chronological periods and also by important topics from contemporary events. The original printing of this work, published in 1944, was received with enthusiastic reviews and went out of print in a few years. An equally warm welcome can be predicted now.