The main character is Daniel, the son of a used book dealer, who finds an obscure novel. The book makes such an impact on Daniel that he attempts to find and read more books written by the same author. This desire to read more leads Daniel into a mystery that touches on issues of love, revenge, and life in post revolutionary Spain.
The summary in the previous paragraph does not to justice to the story. The real power to the story is that he reminds you of what it is about reading that you love. The book grabs a hold of you and just never lets go.
Sometimes a book is great because it grants some new insight about the world you live in and some books are great because they open up a new world to you. The Shadow of the Wind is great because it does both.