This was a gift for my 15 year old.  He loves it.  It fits well in our church bag so he does them at church, which I like because it keeps him from terrorizing his 9 year old brother and being disruptive.  The pictures are very detailed and challenging.  The biggest challenge is finding the right number since they are written so tiny.  But they need to be small since there are so many of them.  There is a good variety of animals. All in all a good purchase.