Le Bon Usage (French pronunciation: [lə bɔn‿yzaʒ], Good Usage), informally called Le Grevisse, is a descriptive book about French grammar first published in 1936 by Maurice Grevisse, and periodically revised since. It describes the usage of the French language, primarily in its written literary form.
Quite extensive (1600 pages), it includes numerous examples and counter-examples taken from francophone literature of various periods, including newspapers, to form a reference for teachers of French, and in particular, authors and editors.
In 1936, the first edition was published by De Boeck Supérieur (then named Duculot). A new edition was published in 1939, and another in 1946. The book was awarded the gold medal of the Académie française. The high praise of André Gide in the literary supplement of Le Figaro in February 1947 contributed to its success.
After the death of Grevisse in 1980, his son-in-law André Goosse, also a grammarian, took over and published the 12th and 13th (1993) editions. The 14th edition was published in August 2007 in a completely new format. The 15th edition appeared in 2011.
Le Bon Usage is available on-line by paid subscription.