Written in 1653 by John Wallis, Grammatica Linguae Anglicanae is generally considered the "first" book regarding English grammar. The reason why "first" is given qualification is because although it regards English grammar it was written in Latin (The first English grammar in English was written by Joseph Priestley (1761) called The Rudiments of English Grammar).
The goal of this work (as well as the works of many of his contemporaries) was to codify the principles of the English language and reduce it to a set of rules and to settle disputed points and decide cases of divided usage. It was also in this work that Wallis related his attempts to teach, with some success, congenitally deaf people to speak.
It is important to note that Wallis was a "self-appointed" grammarian and had no formal "training" in the subject as is apparent in his use of Latin to create a work about English -- much like his work in Mathematics, he felt that one could not describe a system unless one were outside of it; he believed you could not quantify English with English.