I have to express my gratitude to Messrs. Burns and Oates, Messrs. Methuen and Co., and Mr. Martin Seeker for their kind permission to quote from works by Mr. G. K. Chesterton published by them. I have also to express my qualified thanks to Mr. John Lane for his conditional permission to quote from books by the same author published by him. My thanks are further due, for a similar reason, to Mr. Chesterton himself.