I don't understand why someone will like free crypto books and as a matter of fact anything free. Free things are always shit and when it comes crypto/blockchain you should take anything as freebies because you are putting your money to invest.
Instead, the best thing is to buy some of the best Bitcoin and blockchain books from which you can learn something and make your decision in a better. Apart from that, the book will stay with and the knowledge too that you make gained by reading a book that you have bought because bought books inspire us to read also.