It's true that many of the so called investment gurus that publish a lot of trading books make most of their money being an author and public speaking, rather than being a successful trader. In my opinion this doesn't have to be a bad thing and just because we buy one book for 20 USD doesn't make us the sucker. It's always helpful to learn more about the author before buying his book, some successful authors worked as traders in their 20s&30s and only turned to writing books later in life. When it comes to financial literature there are three types of books. The first one is about financial history, they teach us how the past worked and what successful traders bought and sold to become rich. This is informative and can help if we see parallels today to the past, but we can't just copy the trades. The second category is technological and knowledge books that teach us how to do research and analysis of current trends. These are the best type of books as in my opinion as we can learn a lot from them and apply the techniques to various. The third type of financial books are investment recommendations that tell us exactly which assets to buy and sell. Here I would be very cautious and trust blindly on other people what to buy, it's better to make our own research and decisions.