"As a Man Thinketh" is a literary essay by James Allen, published in 1902. The title is influenced by a verse in the Bible from the Book of Proverbs, chapter 23, verse 7: “As a man thinketh in his heart, so is he.” The full passage, taken from the King James Version, is as follows: “Eat thou not the bread of him that hath an evil eye, neither desire thou his dainty meats: For as he thinketh in his heart, so is he: Eat and drink, saith he to thee; but his heart is not with thee. The morsel which thou hast eaten shalt thou vomit up, and lose thy sweet words.”
While the passage suggests that one should consider the true motivations of a person who is being uncharacteristically generous before accepting his generosity, the title and content of Allen's work refer to the reader himself.

Allen's wisdom is timeless. To say nothing of the discipline to be gained by the concept “All things good or bad start with a thought". It is an amazing self-help book.