Hammer's German Grammar and Usage (ISBN 9781444120165) is an English reference book on German grammar.
The 1st edition was published in 1971.
The 5th edition was written by Martin Durrell.
A review of the 2nd edition noted that the book "continues to be the most accurate and complete reference grammar available for advanced English-speaking learners of German".
This article about a book on grammar is a stub.