This book reminds me a little of a Spanish version of Raymond Mortimer's English Grammar in Use and Advanced Grammar in Use, which I used extensively when I worked as an EFL teacher. It combines good notes on usage and formation with clear examples and solid exercises and moves from beginner/intermediate level in Part I to advanced level in Part II. As an intermediate student of Spanish, I used this book to help me brush up on such language points as uses of haber, usage of the preterite vs the imperfect and formation of the subjunctive and found it terrifically useful. I have to take issue with the previous review by Midnight Cowboy - my edition has answers to the exercises in both Parts I and II - those to Part I are on page 289. This edition was published in 2006. Maybe he/she has a different one?