Manhattan GMAT generally uses a red color scheme and tends to be very good quality. People are probably talking about Manhattan GMAT, though sometimes, confusingly, they'll use the word "review" too because... well, you're reviewing for a test, right?

Manhattan Review is an unrelated company. It generally uses a blue color scheme. I don't know much about their quality. Maybe it's great, maybe it's awful, I really couldn't say. From what I've seen it's not so great, but I could be wrong.

Manhattan Review: https://www.manhattanreview.com/
Manhattan GMAT: https://www.manhattangmat.com/

I think you've got the wrong book, marlboro.

I checked the Manhattan Review site and they have their own sentence correction guide. Which is NOT the same as the Manhattan GMAT Sentence Correction Guide(https://www.manhattangmat.com/storeitems ... 26&catid=6). Just check if this is the book you have...

Hope this helps!