Can you tell me anything about Stephen Hawking?
Stephen Hawking was a seminal figure in the science world, very well-known. As an English theoretical physicist, cosmologist, and author/director of research at the Centre for Theoretical Cosmology at the University of Cambridge, his life was science. 
You said he was an author. Can you tell me which books he wrote?
One of his most popular works was a book called The Grand Design, where he paired with Loenard Mlodinow, published in 2010. This work examined the history of scientific knowledge about the universe and explained the 11 dimension M-theory, and also stated that a Unified Field Theory, proposed by Einstein, didn't exist! 
Can you tell me anything else about his discoveries or theories?
So, Hawking was the first person in history to put into the world a theory of cosmology that was underpinned by a union of general theory of relatively and quantum mechanics. What's more, he was a huge supporter of the many-worlds interpretation of quantum mechanics, and it was a large part of his work.
I know nothing about quantum mechanics. Can you tell me something else about that?
Absolutely! Quantum Mechanics (QM), essentially is a fundamental theory in physics that is used to describe the nature of the smallest scales of energy levels of atoms and subatomic particles. Complex stuff. Most theories in classical physics can be derived from quantum mechanics as an approximation valid at large scale, in fact.
Wow. That does sound complicated. I can't say I know much about classical physics, either. 
That's okay! Classical physics just refers to theories of physics that predate modern, more complete/widely applicable theories, so it's probably useful for background knowledge, but not necessarily useful for the advancement of future knowledge, you could say.