This book led to my winning an all expenses paid scholarship to attend a summer language course at the University Of Munich back in 1977. Can't praise it highly enough. Drops you right into the language without the usual dry grammatical exercises.
I used this book during a 2 month Goethe Institut language course in Germany in 1979. The combination of a very competent language teacher, this book and the excellent Deutsch 2000 supporting materials (i.e. work book, vocabulary book and a language cassette that covered each lesson) provided both a firm grammatical foundation and a very practical grasp of spoken and written German. I cannot recommend this book and the Goethe Institut too highly.