Instruct: Classify Amazon reviews into positive or negative sentiment
Query: A must-have for Groucho fans!

Groucho's letters (to him and from him) are many in number, and the correspondents he had...wow! Famous authors, politicians, his family, and his numerous friends...it's a huge list, believe me, and the result is a book full of the many moods of Groucho Marx, and his correspondence with some of the most famous people in the world. Don't miss it!