I once encountered a man who had spent the better part of his life dedicated to translating the Holy Bible into a language that could be understood by a particular region of Africa that spoke a certain dialect.

You can sign up to volunteer for Reading for the Blind and Dyslexic. You read textbooks onto tape, which are freely made available to those with little or no eyesight.

There are lots of ideas in the world already, and if you're a book lover, you might not need to write an altogether new book. You could just take ideas that are already here and make them accessible to others.