Robert Collier 
The Robert Collier Letter Book 

First published in 1931, The Robert Collier Letter Book is by far the top book on writing sales letters. But it goes beyond that. As every great copywriter knows, these techniques are directly transferable to the Internet, whether through web copy or email or whatever. This book earned Robert Collier the distinction of being one of the greatest marketing minds in history. Robert Collier sales letters were successful because he wrote to his readers' needs. As an expert in marketing, his sales savvy and writing expertise placed hundreds of millions of dollars in his clients' pockets.