I never bought the book, and took it cold 1 week after the 7....there's quite a bit of overlap. Study the IA act of 1940, and you'll do fine. Good Luck.

Its not harder than the 7, its just different material. Too many people underestimate the 66 after taking the 7. Its like any other test, you aren't going to pass it if you don't know the answers. I don't know about Knopman. Kaplan was great though.

Blue teeth....2 words... TRAINING CONSULTANTS.... The book is 1/3 the thickness (not for lack of material , but because they teach you the correct things)...also the practice test questions are SPOT ON. IMO, you are taking a big risk if you go with another company. I dont work for them, and I'M NOT JOKING.

Hi: I have wondered the same thing myself. Several people at ML have tried and failed with STC and FireSolutions on the first try (only one person I know used FireSolutions and passed it on the first attempt). PassPerfect is good, but they give you too much material.  Many vendors do this when they really don't know what's on the test and try to cover themselves.  One person told me that they went to a STC live course and at the end of it polled the students to see who had tried and failed the Series 66.  Half the audience raised their hands.  Then the instructor said, 'when you take the test, let us know what some of the questions are, because we really don't know exactly what is on it.' (not joking).

However, I have met at least 3 people that have used Training Consultants and passed on the first attempt.  The book is only 125 pages, but the course material is just what you need to know to pass.  I just took the Series 66 today and passed on the first attempt with an 87%.  About 25 questions were almost identical.  The rest of the material was what I needed to know.

So, I can't recommend them enough.  I hope that it helps.