The book "How to Catch an Elf" is a children's book written by J.M. Barrie. The story follows the adventures of two children, Wendy and John, who try to catch an elf named Tinker Bell. Tinker Bell is mischievous and elusive, but the children are determined to catch her. They use their imagination and creativity to devise a plan to capture her, and along the way, they learn about friendship and trust. The book is full of humor and adventure, and is a delightful read for children of all ages.