Murphy’s central theme is that the power to change one’s life lies within oneself and that this power is rooted in the subconscious and is a part of the universal mind of God. He believes that every person’s experiences, actions, and circumstances are “but the reflections and reactions to [one’s] own thought” (50), and he asserts that the power of the subconscious can be tapped by a transfer of a conscious suggestion to the subconscious under certain ideal conditions. The suggestion is then manifested, or turned into reality, by the subconscious.

He argues that great people of all ages knew and used this secret to tapping into the power of the subconscious, and he believes that every major religion and philosophy shows that what people think and believe affects their lives. These arguments are often supported by quotes from the King James Bible, which Murphy uses to establish a level of credibility with Christian readers as he builds his central premise. Each chapter of the book then presents a specific aspect of this central theme, and he outlines how the process works, how to harness it for self-improvement, and how it can bring happiness or heal the body and mind.