Samuel Johnson wrote a book called "A Grammar of the English Tongue." It is a complete guide to the rules of English grammar and syntax. It is meant to help people improve their writing and speaking skills. The book is divided into several sections, covering topics such as parts of speech, syntax, punctuation, and spelling. It also includes examples of correct and incorrect usage, as well as exercises to help readers practice applying the rules. Johnson's writing style is clear and straightforward, making the book easy to understand even for those with little prior knowledge of grammar. His approach to grammar is prescriptive, meaning that he sets out rules for correct usage rather than describing how people actually use the language. Even though it was written more than 250 years ago, "A Grammar of the English Tongue" is still a good book for anyone who wants to learn more about the English language. Its influence can be seen in many subsequent works on English grammar and usage.