I bought a Macmillan's Dictionary for Children "fully illustrated" for DS when he was 5 and even at that age, a lot of the words he wanted to look up were not in it. He still likes browsing it at age 7 (like a picture book), but when he really needs to look up a definition or spelling, he uses a Webster's college dictionary. I got him a new one to replace my beat up one from 1981. Nan