Is the book The Power of Your Subconscious Mind, by Joseph Murphy, Christian?
I have not read the book, but I did find the following description from the publisher:
"I have seen miracles happen to men and women in all walks of life all over the world." -- Dr. Joseph Murphy. At last, a great new scientific discovery brings the incredible force of your subconscious mind under your control. Here are the simple, scientifically proven techniques and the astonishing facts about how your subconscious powers can perform miracles of healing. How lung cancer has been cured and optic nerves made whole again. How you can use the newly discovered Law of Attraction to increase your money-getting powers. How your subconscious mind can win you friends, peace of mind, and even help you to attract the ideal mate. How your dreams can help you solve problems and make difficult decisions -- or warn you of potential disaster. Prosperity, happiness and perfect health are yours when you use The Power Of Your Subconscious Mind.
Just from the description, I see a claim of miraculous powers attributed to men and not God. It reminds me of the warning about false teachers who "mouth great swelling words, flattering people to gain advantage" (Jude 16). Notice the emphasis on power and greed in the book's description and realize that this too is a warning sign of a false teacher. "By covetousness they will exploit you with deceptive words ... For when they speak great swelling words of emptiness, they allure through the lusts of the flesh, through lewdness, the ones who have actually escaped from those who live in error" (II Peter 2:3, 18).
Perhaps this is why the book is already out of print.