Although no specific book is a definitive standard guide to correct English grammar, the New Fowler's Modern English Usage and Garner's Modern American Usage are two relatively modern and authoritative texts on proper grammar usage. However, some aspects of grammar use depend on personal preference or country of origin.
The New Fowler's Modern English Usage, edited by R.W. Burchfield, is useful because of its careful delineation between British and American usage and formal and informal writing. Garner's book, on the other hand, focuses solely on American usage, and it highlights errors found in several older usage guides. These types of errors and editorial preferences are the reason that no gold standard usage book is agreed upon.