Written with input from child psychologists, the Hand-in-Hand series of books helps children navigate their way successfully through various key developmental experiences of childhood. Caillou is feeling very proud: he knows how to use the potty just like grown-ups and has graduated out of diapers, except for at night. Even though Caillou really wants to use the big toilet all the time, sometimes he's just too sleepy to wake up. Daddy gives Caillou a step stool and a soft toilet seat to make it easier for him to use the big toilet. He understands how much Caillou would like to be out of diapers and that with time and patience, Caillou will succeed.