I started doing an English Language A-level and this book was on the recommended reading list. So I purchased it and duly ploughed my way through.
It is the basics of English grammar. It is a bit confusing as it talks about word types at the end and sentence structure at the beginning but by the end the sentence bit fell into place. You should probably read the word chapter first, then the ones about nouns, then verbs, then other types of words and save sentences until the end.
My only criticism is that there are no answers. I am an Accountant and so I like to know whether I am right or wrong. Most of the progress checks and tests you can guess at but I would have liked to have been able to benchmark whether I was hitting the nail on the head or not.