In Chapter 27, Maniac teaches his friend Grayson to read by acting as his own personal dedicated teacher, starting with the alphabet and moving Grayson slowly up until he can read words, then sentences, then entire books.
They start by buying some cheap old picture books that were for sale at the library as well as some chalk and a small blackboard from Woolworth's.
They start at the beginning, with Grayson first learning the names, shapes, and sounds of the letters, which takes three days. A few weeks later, Maniac has helped Grayson read short words (ones with just one syllable, like "cat" and "this" and "find") by blending the sounds together. Vowels were very hard for Grayson to learn--understandable, since they make different sounds according to complex rules, most of which have exceptions--but Maniac doesn't let Grayson give up. He just keeps coaching his old friend like a patient, knowledgeable baseball coach would do.
By the end of the chapter, both Grayson and Maniac are thrilled when the old man reads his first sentence: "I see the ball."
Then, as Chapter 28 opens, Grayson reads an entire picture book from cover to cover by himself. It's extremely difficult and takes almost an hour. But now he's a reader.
The whole experience of Maniac teaching Grayson to read really shows you a lot about their characters: they're extremely determined, they work hard, and they function well as a team. Maniac has improved Grayson's life by helping him achieve this serious accomplishment (becoming a literate adult) and, likewise, Grayson has improved Maniac's life by allowing him to accomplish something a lot more meaningful than, say, untying the world's biggest knot.