This app provides a nice structure and approach to present a fairly comprehensive summary of English grammar. I very much like the idea. However, given the price, I would have expected more attention to detail, as minor typographical or spelling errors abound.There are, of course, minor differences between English dialects and it would be nice if this reference identified its target dialect, or even better, contrasted differences, particularly between American and British dialects.Having made the relatively expensive investment, I can only hope they continue to update the contents, correcting errors and even expanding it. It is a useful reference, and could grow to be a valuable and trusted one.