Providing the book is interesting, then a good book about Lucid Dreaming provides a great deal of suggestion to your subconscious that you would appreciate a Lucid Dream. Yes, certainly, the same time applied to actively suggesting Lucid Dreaming and working upon Lucid Dream Checklists and Reality Checks would be equally or even more efficiently effective. But with the amount of time it takes to read a book ( and all that time counts for influence in the Mind) and since most books are not really all that expensive, I would say that books are not a waste of time or a particular waste of money.

But do yourself a favor and try to get reviews of these books. I recently got a book, and its emphasis was supposed to be upon Shamanistic Dreaming. Well, that was the author's angle but all he did was rehash all of the old Dream Seminars from all of the old Dream Dinosaurs that had come before and already plowed those fields. to read Patricia Garfield and Carlos Castenada rehashed by somebody with little worthwhile knowledge of his own was annoying, and rather turned me off to dreaming than to subconsciously encourage it.