The Elements of Style by William Strunk Jr.

The Elements of Style is an American English writing style guide. It is one of the most influential and best-known prescriptive treatments of English grammar and usage in the United States. It originally detailed eight elementary rules of usage, ten elementary principles of composition, and "a few matters of form" as well as a list of commonly misused words and expressions. Updated editions of the paperback book are often required reading for American high school and college composition classes.