Professor Hawking explains his theroies in very plain language. He also allows in his lecture the possibility of the existence of God. One of his argumdnts for God, is that some of what we observe in the Universe is too precise in it's mesurements (a little too much and the Univere expands so much that there would be non left today since the Big Bang, and not enough of some measurements and the Universe would have contracted back to it's state before the Big Bang, never expanding beyond that.)
He also shows a lot of his well know charm and humor. One of the first things he says is that he apoligizes for the "American" accent of his voice, he has not yet been able to teach it proper English.
First I thought that voice would be annoying or distracting, but no. The annunciation of the sound of his voice is very very good. Since you may have heard him speak, then it simply becomes the voice and accent of the well know Astrophysicist.
I am not a genius by any means, but I understood many and much of what Professor Hawking was talking about. Much of what he says are reasonings and science that I've grown up with. Interesting thing is, his mentioning the existence of God is something that I believe as well, that God if he exists,is just the most interesting and advanced scientist we have ever known. For 3 and a half hours it is well worth your time to give these historic lectures a try.
Very enlightening science.