As a Man Thinketh is a self-help book by James Allen, published in 1903. It deals with the power of thought, particularly with the use and application of thought to happy and beautiful issues. The book was described by Allen as "a book that will help you to help yourself."

Quotes from the book:

"Men do not attract what they want, but what they are."
"Men are anxious to improve their circumstances, but are unwilling to improve themselves, they therefore remain bound."