The Easy Grammar series utilizes the "Prepositional Approach" to teaching grammar. First, the student is taught the prepositions, and after that he is taught to take prepositional phrases from the sentence, leaving only the bare bones: the subject and predicate. From there, they branch into the other parts of speech and cover capitalization and punctuation.
The books are quite plain; there are no pictures. But while the format is unattractive, the content is excellent. The texts include the student workbooks, and can be used on their own. However, the answers are included on the facing page, so unless you cover that page and trust your student not to look OR you have access to an inexpensive copier (one that costs less than 4¢ per page), we recommend that you buy the additional, separate workbook.
Please note that this is not a complete language arts program on its own. It is only grammar, with a very small section of writing at the back of each book. It is necessary to supplement it with additional writing, reading comprehension/literature, spelling/vocabulary, and perhaps some sort of speech material for a full coverage of English.
We have sold hundreds of these texts and received mostly positive feedback. Some customers do not like the plain format; a number think it moves too slowly for their children. The biggest complaint we have heard is that some children do not test well after using it. But usually, we hear that their children never finished the book. Since most of the grammar mechanics material is towards the end of the courses, that makes sense. So we think it is important to make sure your students complete those sections if you want them to test well!