Do I understand string theory? Not sure.

Do I understand M theory? A little bit but don't ask for any algebraic reasoning.

Do I know exactly what a Calabi-Yau is? Not really but I think they look a little like the hair balls from my cat.

This is the second time I've equated quantum physics and all its detours to a hair-ball. That's because I can study a hair ball and still have no idea what it is for and why they exist. String Theory and the elusive TOE is in the same category. I could go on my entire life not knowing about them but now that I do, I need to know why. Newton, Einstein, Feynman, Hawking, and my cat can't all be right. Or can they?

That is essentially the dilemma of string theory and the book. Greene does a great job of putting everything in layman's term but there is a point which he must exceed the intellectual ionosphere and soar into the incalculable. I really like this type of book. The challenge is the fun. But rest assured when the scientists get their act together and write an Idiot's guide to The Unified Theory Of Everything, I'll be the first in line.

P. S. Hair balls and string theories have something else in common. Once you tore one apart, you can never get your hands clean.