In 2006, Princeton University Press published a new edition with a new introduction by Anthony Zee. He introduces Feynman's peculiar take at explaining physics, and cites: "According to Feynman, to learn QED you have two choices: you can go through seven years of physics education or read this book".
The four lectures
1. Photons - Corpuscles of LightIn the first lecture, which acts as a gentle lead-in to the subject of quantum electrodynamics, Feynman describes the basic properties of photons. He discusses how to measure the probability that a photon will reflect or transmit through a partially reflective piece of glass.
2. Fits of Reflection and Transmission - Quantum BehaviourIn the second lecture, Feynman looks at the different paths a photon can take as it travels from one point to another and how this affects phenomena like reflection and diffraction.
3. Electrons and Their interactions - The third lecture describes quantum phenomena such as the famous double-slit experiment and Werner Heisenberg's uncertainty principle, thus describing the transmission and reflection of photons. It also introduces his famous "Feynman diagrams" and how quantum electrodynamics describes the interactions of subatomic particles.
4. New Queries - In the fourth lecture, Feynman discusses the meaning of quantum electrodynamics and some of its problems. He then describes "the rest of physics", giving a brief look at quantum chromodynamics, the weak interaction and gravity, and how they relate to quantum electrodynamics.