"Ask Me, I'm Mr. When" is the fourth book in a series of five. This book is an easy "read-aloud" book that is intended to have children recognize words that are familiar to them. "When" is one of the questions that children become curious about. They have questions that concern time and settings. The book begins to have children learn the time of day; and, when there is a routine in their lives, it helps them get acquainted with a pattern in their day. It is the fourth "must read aloud" book in the series of five.