Books are probably the oldest way of learning a language and there are real benefits to them. You can see what’s on the page, it doesn’t go away, and they are relatively portable. The downside is that you aren’t getting immediate feedback on what you are learning and while you can learn vocabulary and grammar, conversation will come very difficult. It’s also hard to get tones correctly out of a book so you may end up sounding like you have marbles in your mouth when you are asking where the bathroom is. Many of the books have audio components but if you are like me you probably lost them.