I edit many personal self-help books. My valued clients are consultants, coaches, and personal development experts who write books in order to educate and uplift their readers, and also to attract clients.
The self-help universe is surprisingly small, and many of my book clients are inspired by self-help leaders including Tony Robbins, Stephen R. Covey, Ken Blanchard, Brian Tracy, Mihaly Csikszentmihalyi, and Viktor E. Frankl.
Often, my client will quote a famous self-help guru in his or her own book. Sometimes these quotes can be a paragraph or more. That’s when you need to start being concerned with copyright infringement.
When I see lengthy quotes, I ask my client to become familiar with copyright law, and especially the concept of fair use. Under the legal concept of fair use, you can reproduce short segments of another work if you are discussing it or reviewing it. The key thing to note is that the US Copyright Office says that “Copyright protects the particular way authors have expressed themselves. It does not extend to any ideas, systems, or factual information conveyed in a work.” This means that if you re-write or “spin” the original text and use different words to express the same idea, you are safe, and you need not even give a citation. Many self-help authors do this. They simply re-write the ideas expressed in other books.
The Copyright Office page on fair use is here.
The same applies to images or charts taken from other works. If you want to be assured of having ownership of your book and everything in it, you should simply have the images re-drawn by someone so that they are original. It may also be the case that certain ancient images are in the public domain. Photographs tend to be unique, so you can’t “re-photograph” the scene. But you can purchase the rights to original photos from a stock house. I urge my clients to never, ever use clip art or images from the Internet.
I’m not a copyright lawyer, so this is not legal advice. If in doubt, you should consult an attorney. The only way to not be in doubt is to make sure that you own every word and every image in your book.

– Thomas Hauck, freelance book editor, provides a wide range of literary services to both first-time and established authors.