I found it very clear--to the extent that all that quantum and cosmological chicanery can be rendered intelligible--but not revelatory. Hawking has already put forward in another book the mind-bending idea that time may have not beginning, being like a point on a curved surface, such if you go back far enough towards it, you get to a point where you no longer make any further progress backwards, but just start going forwards again.
One fact I found particularly intriguing was that you can get quantum interference effects with bunches of atoms as well as with electrons. Hawking suggests something at least as large as a virus might even show them. It struck me that, since you don''t get these effects at an everyday macro level, there must be a magnitude at which they no longer occur, and a necessary physical reason for why they don't. However, Hawking doesn't hint at what that reason might be.