The following resources have been of reference during my work on Travel in Grammar. The work is in progress.
Practical English Usage
by Michael Swan
New in stock on August 13, 2019
The 4th edition of a well-known grammar “problem book”, that is, one to address likely difficulty. The edition I used had an easy index, so it met the curious expectation as well. Worth reading. More→
Practical English Grammar
by A. Thomson and A. V. Martinet
New from $29.27 / Used from $2.36
A very detailed approach some people may find too focused, but definitely worth a read, for those things that do not change in language every so often.
English Grammar in Use
by Raymond Murphy
English Grammar in Use with Answers can make a great companion to the intermediate learner; explanations are simple and the book has many practice exercises. More→