William Strunk taught writing to Cornell students for 46 years, and he used an early version of Elements as a classroom handbook. One of his students, E.B. White, later edited the volume; it was published in 1959, and it’s still one of the best style guides we have.
The book is divided into several short sections – one on usage, another on principles of composition, and then a few guidelines on form and style. Strunk corrects for common writerly mistakes, but he also explains the consequences of those mistakes. Strunk’s famous admonitions – “Use definite, specific, concrete language” and “Omit needless words” – are the kinds of advice that most writers never stop needing to hear.