Hi Mrdlm,

Manhattan Prep publishes new strategy guides every few years, to reflect ever-improving pedagogy. If you're buying new copies, it's best to buy the newest edition: right now, that's our 6th edition: https://www.amazon.com/Complete-Strateg ... +prep+gmat

Any edition of our books would contain all of the content you need to study for the GMAT, as the content doesn't change. We just like to update how we package / present / teach that content.

We no longer update our books with each new edition of the OG (we used to publish the OG question #s at the back of each guide), as GMAC will be publishing a new OG every year, and we publish new editions of our guides about every 3 years. So again, any edition of our books will fit any edition of the OG. When in doubt, buy the newest versions of each.

Good luck!

GMAT Interact is a responsive video instruction platform. Rather than a static video that you watch passively, Interact is dynamic - it will prompt you to answer questions as you go, and it will adapt what you see based on whether you get questions right or wrong. Our very own Manhattan Prep instructors conduct these video lessons in a warm and engaging way, so students often tell us that it feels like private tutoring!

It is offered in 2 ways:

1) As part of our self-study package. With a full self-study package, you will get all of the books and resources you need to go along with the video lessons, as well as a syllabus to tell you exactly what to do. Or if you already have books, you can simply purchase the suite of video lessons. If you opt for this path, you will have access to Student Services support, but you will not interact live with instructors (except through workshops or forums).

2) As a compliment to our live courses or tutoring packages. With these, of course, you will have lots of individualized interaction with our instructors.