I have to admit there are some grammar issues, specifically comma usage. In addition, certain events and the years in which they took place should be clearer to the reader. However, the information is solid and the details are sufficient. Speaking from a writer's perspective, a book with this amount of information doesn't happen overnight; it takes a lot of late night hours to create even the smallest of books. When you consider the amount of information within this book, and the author's decision to offer it for free, it's a pretty good deal despite the errors.