What is the best English grammar book for teachers and writers?

[constantinusphilo]

I am looking for the best and most comprehensive Grammar book for teachers and those who write in English. Up to now, I have been regularly consulting Quirk's Comprehensive Grammar. Any other suggestions?

 

[Piscean]

The most practical I have found is Swan's Practical English Usage, now in its fourth edition.

 

[jutfrank]

It depends what you want to use it for. I would expect EFL teachers and writers to want quite different things.

As a teacher, I like Parrott's Grammar for English Language Teachers.