There are many ways to learn. However, I think books are one of the best. Having read over 1,200 books I would say that! Of course, there is more to learning any subject than reading but, I think there are still many tangible benefits to reading books and I would like to outline some of those here.
Reading books improves your vocabulary: Reading good books (and by that I mean primarily non-textbooks) improves your vocabulary inasmuch as you are quite likely to encounter words you have not heard or used before and assuming you look them up you can then add them to your reading, and possible, speaking vocabulary.
Reading books improves your writing: Just as becoming a better musician entails listening to other good players, becoming a better writer entails reading other good writers. The best books are ones that allow you to improve your own ability to express your thoughts in writing by showing you the best writing techniques in action. It’s one thing to see good writing examples in a textbook, but quite another to see them applied.
Reading books improves your attention span: To fully digest an author’s thoughts in a book requires sustained attention. You need to be able to focus on and analyze extended arguments, illustrations, and narratives. The skills required for close reading are useful skills in other areas of life as well and a great way to cultivate these skills is by seeking out good books and sticking with them.
Reading books deepens your knowledge: You can learn the basics of a subject by reading articles and encyclopedia entries but to really get deep and detailed knowledge you need to read books. Authors can provide much more elaborate arguments and narratives in books than they can in any other format. The real payoff of your sustained attention to an author’s ideas is the depth of knowledge you can gain from it.
I recently completed a MOOC titled "The History and Future of Higher Education." One of the assignments was to create an outline for a university. I choose to create one around a curriculum based largely on reading books. However, I suspect that the very idea of reading books as a basis for a curriculum is becoming less fashionable. The argument is that there are so many other ways of gaining knowledge now with digital resources that the place for books in a curriculum is shrinking. Besides, students today simply will not read books so why should we assign them? But, it seems likely that if students had been encouraged to cultivate a love of reading early in their life they would carry this with them to high school, college, and beyond. A reading-based curriculum encourages that love of reading. Start with the fun of reading and learning and let the rest of the benefits take care of themselves.