The discourses included in this volume have been delivered as addresses on various occasions which are duly noted; the only exception is The Anatomy of Some Scientific Ideas, which is now published for the first time. These dis courses fall into two sections, the first five chapters deal with education, and the remaining three embody discussions on certain points arising in the philosophy of science. But a common line of re?ection extends through the whole, and the two sections in?uence each other. I have left in each chapter the reference to the particular occasion of its first production, and I have not sought for a verbal consistency cover ing perplexity. But the various parts of the book were in fact composed with express reference to each other, so as to form one whole. I have to thank the Syndics of the Cambridge University Press for permission to republish the contents of Chapter V.