I want to suggest a few grammar books that I think make for great self study.
First, I think the Azar series is great. I’ll link here to the three books in the series which always have and probably always will be easily identifiable by their colors: red for beginner, grey/black for intermediate, and blue for advanced. Some people may find the
Perhaps, even better is the English in Use series. I’m most familiar with the intermediate book in the series. What I like about this series is that they are colorful and inviting. They also explain grammar in a very user-friendly way which makes them good for students who maybe have missed something in their grammar class.
A few teachers have talked about their students loving the Focus on Grammar series. I’ve taught from the level 4 book. I found that my students got the explanation of relative clauses a lot better in this book than they did in the book I was assigned.
Finally, if you are working on the IELTS, you might check out this book. This book, simply called Grammar for the IELTS, covers a lot of things you probably are going to have trouble with on the test such as non-count and count nouns and nominalization. The Manhattan Sentence Correction book is about as close as it comes to a grammar book for the GMAT.
Enjoy your reading!