OCD by Sid Van Roy

Either way, your knowledge will increase by going through this concise guide.
This book focuses on ways to help people with the disorder, as well as on methods to handle compulsive tendencies. The last and longest chapter of the book goes over a number of questions and answers about children with the disorder, questions that have been common in the community.
There is a lot of great material in here. I invite you to give it a try.