My son was almost 4 when a relative gave him this book and set of five Monkeys. We were at a restaurant and he did not stop playing with them or the book. Right there it was it hit. But No, two years later he STILL loves these monkeys and the book!! One or more have gone to every major event, trip, restaurant in the land with us and bought us time and good behavior to boot!! I'm on today buying another set and sending the link to a friend who's grandchildren fell in love with them at our house! If you are getting one set, I would recommend getting 2 and squirreling the second set away as a gift or "secret replacement" should one of the monkeys "go missing" as they are not easy to find/replace. Just tried and true advice from this parent! (I know several reviewers have commented on the velcro not holding up but given the number of times they are used before it gives up the ghost, not a deal breaker. Also a very simple fix is pick up the "Mega Strength" sticky backed velcro at a hardware store and peel & stick a small piece on each side right over the original pieces and Bam! you are back in business in 10 seconds!)