Reader's Digest word power dictionary:

A good command of English is the key to success in the modern world. Success at school, at work, in business and in social life depends on being able to use words correctly, confidently and persuasively. The purpose of this book from Reader’s Digest is to help anyone who has ever felt the need to communicate more effectively do just that. Driven by its status as the world language, English is constantly changing and adapting itself with borrowings from other languages, science, computerspeak and pop culture. This has led to confusion, even among mother-tongue speakers, in how to use words correctly, particularly because the spelling is so often at odds with pronunciation. Another difficulty is the widespread use of idioms, which, while enriching the language, leaves many of us unable to use it to its full potential.