When I recommend a book, it is a book I’ve read or purchased and have found useful. If I find an author whose works are overall good, I may also recommend additional titles that I have yet to read.
When I recommend products, they are either products I have purchased and used (and found useful) or that would be useful to me if I had a need for them.
Some of the books and products I recommend have affiliate programs that pay a commission when someone follows a link and makes a purchase. My decision to recommend books or products is based on the usefulness of the book or product to me, not on whether or not an affiliate program is available.
All recommendations I make are made in good faith and with the belief that anything that has helped me will also help others. But if you believe my participation in affiliate programs taints my objectivity in making recommendations, you should discount any such recommendations.
As with any recommendation, examine the books or products for yourself to determine whether or not they will help you. It is my belief that what helps me will also be of benefit to others, but not everything works for everyone, so I urge you to practice due diligence in any purchase.