"I don't want to wait more than a year and a half or two years between books"

Max Cannon's quote suggests that he does not wish to wait too long between the release of his books. He is expressing his desire to have a consistent stream of books coming out, instead of having long spaces between them. This might be due to the fact that he wishes to keep his readers engaged and interested in his work, or because he wants to keep his name in the public eye. It could likewise be due to the fact that he wants to keep his writing profession going and keep a constant income. Whatever the factor, it is clear that Max Cannon does not want to wait too long in between books. He wants to keep his readers engaged and his career going, and he wishes to do it in a timely manner.