You might consider this a book within a book. A 15 year old autistic boy, Christopher Boone, is asked by one of his teachers to write a book. Since he enjoys reading mysteries (Sherlock Holmes is his favorite), and he just happens to have a mystery to solve, he decides to make his book a mystery and that is what we are reading in this book. The story opens with Christopher coming across his neighors dog lying dead in the yard with a garden fork stuck thru him. The question then becomes, "Who killed Wellington"? 
 As Christopher investigates, he ends up solving a mystery he didn't even know existed. And his book gives us not only an up close look into his life, but how he sees the world from the inside out. 
 Simply told and quickly read, it was a good read!