I have been teaching English as a foreign language for 8 years now and this is the BEST book I have ever come across and the only book I recommend to my students. Whilst many other well known grammar books are best used for reference this book gives quick direct explanations allowing people then to really use it in the exercises which follow the explanation. Because it tends to 'group' tenses or grammatical fields together the student are forced to try to work out which grammar tense is the correct option whilst most other grammar books either don't have exercises included or just tend to concentrate on one grammar point making the exercises futile as the English language is not segmented into compartments but demands a complex and varied use of grammar! Great explanations (the next best thing to a teacher - it really TEACHES grammar) and great exercises created to check if the students have really understood. Can a grammar language practice book get better than this?
Have also used the First Certificate and Advanced books and the same goes for them!