Photons, Schmotons by John Baez, Michael Weiss
Publisher: University of California 2002
Number of pages: 47
Did you ever wonder 'What the heck is a photon, anyway?' Well, this question quickly gets you into pretty deep waters. Not only do you need to understand Maxwell's equations and quantum mechanics, you need to understand how they fit together into a marvelous theory called 'quantum electrodynamics'. These webpages won't teach you quantum electrodynamics. But they'll give you a little nudge in the right direction.
Science Physics Atomic Molecular & Optical Physics