Wallace D. Wattles, 1910. Complete text.
Wattles opens by refusing to apologise for the subject, and the book is better for it. His claim is narrow and testable: there is a particular way of thinking and acting which produces prosperity, it can be learned, and it does not depend on talent, environment or thrift.
The two chapters that carry the book are Thinking In The Certain Way and Acting In The Certain Way. Together they make the point that most modern material on this subject drops, which is that the mental work is not a substitute for the day's work but the thing that directs it. Wattles is blunt about people who visualise instead of acting, and blunter about people who act without a clear image.
It is also the book behind a great deal of later prosperity writing, usually uncredited. Reading the original is the fastest way to see what has been added and what has simply been repeated.
Transcribed from the Project Gutenberg edition. First published in 1910 and long out of copyright worldwide.