James Allen's most famous book, As a Man Thinketh, was originally published in 1902. It is now considered a classic self-help book. Its underlying premise is that noble thoughts make a noble person, while lowly thoughts make a miserable person..

Allen's books illustrate the use of the power of thought to increase personal capabilities. Although he never achieved great fame or wealth, his works continue to influence people around the world, including the New Thought movement.

Some of the Greatest Quotes From As a Man Thinketh:
- Men do not attract what they want, but what they are.
- A man is literally what he thinks, his character being the complete sum of all his thoughts.
- Cherish your visions. Cherish your ideals. Cherish the music that stirs in your heart, the beauty that forms in your mind, the loveliness that drapes your purest thoughts, for out of them will grow all delightful conditions, all heavenly environment, of these, if you but remain true to them your world will at last be built.
- The soul attracts that which it secretly harbors, that which it loves, and also that which it fears. It reaches the height of its cherished aspirations. It falls to the level of its unchastened desires - and circumstances are the means by which the soul receives its own.
- Men are anxious to improve their circumstances, but are unwilling to improve themselves, they therefore remain bound.
- Every action and feeling is preceded by a thought.
- Right thinking begins with the words we say to ourselves.
- Circumstance does not make the man, it reveals him to himself.
- You cannot travel within and stand still without.
- As the physically weak man can make himself strong by careful and patient training, so the man of weak thoughts, can make them strong by exercising himself in right thinking.
- Every man is where he is by the law of his being; the thoughts which he has built into his character have brought him there, and in the arrangement of his life there is no element of chance, but all is the result of a law which cannot err.

As A Man Thinketh - Lydbok, Engelsk, 2018