I don't mind alternative histories and this story did go into some history events. No 'grammar' problems in the book that I noticed, but the wording style and the way some things were explained just did not grab me and made it a hard read in part.
I am giving it three stars mainly for the ideas in it, and also because the Author did cover or think about things (even if they were spelt out in a fairly simple/direct way which was hard to take at times). Perhaps better for a younger audience, but then the political/history aspects would probably pass over their heads. Also if you are American (and I am not) some aspects might appeal more, but I strongly suspect that your political leanings will play a large part as to whether you like the story line and, I expect, whether you possibly reach the end of the book.