Instruct: Classify the given Amazon review into positive or negative sentiment.
Query: A Classic in Mathematical Exposition

Richard Courant was a master of mathematical exposition, and this is one of his best works. In keeping with Courant's philosphy, this book is free from the excessive abstraction often found even in introductory calculus textbooks. Nevertheless it does not gloss over difficulties in the material, and is in no sense an easy book. This book a complete rewrite of Courant's original "Calculus" which first appeared in German. An especially good chapter is the one on the "Theory of Plane Curves."