Wallace Delois Wattles wrote a number of books including Health Through New Thought and Fasting, The Science of Getting Rich, The Science of Being Great, The Science of Being Well, and a novel, Hellfire Harrison, but it is for his prosperity classic, The Science of Getting Rich that he is best known.

Little is known about Wattles' life. He was born in the USA shortly after the civil war, and experienced much failure in his earlier years. Later in his life he took to studying the various religious beliefs and philosophies of the world including those of Descartes, Spinoza, Leibnitz, Schopenhauer, Hegel, Swedenborg, Emerson, and others. It was through his tireless study and experimentation that he discovered the truth of New Thought principles and put them into practice in his own life. He began to write books outlining these principles. He practiced the technique of creative visualisation and as his daughter Florence relates, "He wrote almost constantly. It was then that he formed his mental picture. He saw himself as a successful writer, a personality of power, an advancing man, and he began to work toward the realization of this vision. He lived every page ... His life was truly the powerful life."

HIs most famous book, Science of Getting Rich,  is free online. Some of his famous quotations are :

"You don't have to get something for nothing, but can give to every person more than you take from him."

"By thought, the thing you want is brought to you. By action, you receive it."

"When you make a failure it is because you have not asked for enough. Keep on, and a larger thing than you were seeking will certainly come to you."

This seems to be the earliest known principles that are in line with what we know today about positive thinking and the laws of atrraction.