One of my seminary professors once said "before you buy your groceries this week, buy this book."
Having purchased and well worn my copy, I can tell you there was no hyperbole in his recommendation. Muller with great care, insight, and clarity explains the rich vocabulary of the Christian faith. Muller's Dictionary is a wonderful resource that pastor-scholars will find themselves returning to time and again. Particularly it is an essential resource for anyone engaging in theology proper.