The book is written by some of mediocre faculties at Hunter College of City University of New York for the first time German students. It contains some 20 boresome and the absurdest dialogues each of which comes along with German words and grammars that are irresistably ill-organized. So much so that many students who seriously wants to persue a German study have to rely, in the end, on the secondary resources. I will point out a few outstanding flaws among many in this book.

1) Grammar is generally not comprehensive enough, and some of the important categories are left out due to the more dialogue-based presentation of the book.

2) Listening practice is virtually unavailable.

3) Exercises are only partial and severely limited.

4) Among dialogues, translation is sometimes omitted for "reading practice". Moreover, some of new words in dialogues are not even listed in the vocabulary.

This much would be enough to convince you the value the book contains.
The book is simply not sufficient to gain a average college-level skill of German language. If you happen to be a German student using this book as a primary-text, I strongly suggest that you should use "Hammer's German Grammar and Usage" as a reference. "Schaum's Outline of German Grammar" is also good for exercise.