Caples was one of the most capable men to write on the effectiveness of advertising. Because he worked in direct-mail advertising most of his life. The book is full of Gems and suggestions that are as applicable today as they were in his days. Tested Advertising Methods is as basic to advertising as the alphabet is to mankind. I also suggest; How to make you advertising make money also by Caples and Ogilvy on Advertsing by David Ogilvy.