What are the size limitations?
40 page book is about as the least amount of pages possible (very hard to bind a book shorter than that). Upper limit is 550 pages depending on paper weight (one sheet of paper equals 2 book pages). Dimensions are maximum 8.5″ x 11″ (technically slightly less as at least a little bit of paper is trimmed off to have a good edge), down to a minimum of 4.5″ x 4.5″.