Mediaeval Socialism is a historical political science classic by Bede Jarrett. The title of this book may not unnaturally provoke suspicion. After all, howsoever we define it, socialism is a modern thing, and dependent almost wholly on modern conditions. It is an economic theory which has been evolved under pressure of circumstances which are admittedly of no very long standing. How then, it may be asked, is it possible to find any real correspondence between theories of old time and those which have grown out of present-day conditions of life? Surely whatever analogy may be drawn between them must be based on likenesses which cannot be more than superficial.