I haven't posted here in a while, and it feels good to be back. Here's my dilemma. I have taught AP Mechanics and Electricity & Magnetism at a private school for a few years now. My background is not in Physics, however, and therefore I have not taken some of the standard courses that a Physics major would take. I feel like I am doing a disservice to my students, who occasionally ask questions outside of my area of expertise. To give you some background, my undergraduate major was in Materials Science Engineering at Cornell U. The extent of my Physics classes were Mechanics, E & M, and Optics & Waves. I have since obtained a PhD in Geophysics at Penn State, which reinforced some of the previous concepts and added new ones. For instance, I would like to improve my understanding of quantum physics. I know that Kittel is the "bible" of quantum physics, so to speak, but it makes for slow reading. Can anyone recommend additional reading that might shed light on the issue? (I have read Feynman's QED, which was easy to understand.) In addition to quantum physics, what other subjects do you think a well-rounded physics teacher should know? And no, I'm not talking about my beer gut.