Merriam Webster's Dictionary of English Usage is a style guide in dictionary form published by Merriam-Webster, Inc., of Springfield, Massachusetts. It is currently available in a reprint edition (1994) ISBN 0-87779-132-5 or ISBN 978-0877791324.
It is critically acclaimed by linguist (Geoffrey Pullum, who calls it "the best usage book I know of... utterly wonderful."[1] It is known for its historical scholarship, analysis, use of examples, and descriptive approach. It has more than 2,300 entries, and includes more than 20,000 quotations from prominent writers.[2]
A concise version is also available.