If a book, after you finish reading it, you find that it is useful to you, not a single sentence, then to you, it is a worthless book, regardless of who wrote it. If even one sentence is useful to you, then it has value. The purpose of reading a book is to gain more inspiration, ideas, methods, and tools to help solve real-world problems, not to expect that after reading a book, you will be able to solve all your issues related to making money, marriage, and so on.