Yeah, sure. Hawking's A brief History of Time is a pretty good place to start when you want to learn about physics. It's good that you went there, because lots of other books would have been much too dificult. Anyways, yeah, a singularity is something that is found at the center of a black hole. Basically, what it is, is a ball of matter that has been crushed infinietly small. It is where all the mass of the black hole is, crunched into an ubbelieveably small "ball" of matter. Quantum theory is a law that governs all the different sub-atomic particles. I'll assume you know a bit about protons, neutrons, and electrons to not really mention those except for reference. But try to imagine particles similar in size, mass, and other properties to the above particles. Quantum theory, also known as quantum mechanics, tells how these particles act with other similar particles and the space around them. Some of the particle catagories that have been found are: baryons, mesons, and leptons. I don't know how much more I can say about this subject without going into college level physics. If you have any more questins, just post them and I'll get back to you.