Of the many books available to writers, On Writing Well outshines them all. Written by William Zinsser, this book succinctly describes how to write well, profiling important tools such as voice, interviews, beginnings/endings, and different beats.
Due to Zinsser's compelling writing style and love of real-word examples, readers get a complete picture of the best way to write coherently. The book breaks down what writers should avoid. But it's never too full of itself; there is a humility to the book I found refreshing.
Just like Strunk and White's The Elements of Style, On Writing Well should be re-read every year. Its advice should be mentally bookmarked by any writer or journalist; and I think its lessons could even apply to fiction writers.
What book on writing do you like?