The 16 lectures cover a wide range of advanced theoretical physics, including:
Because these were postgraduate lectures given in the afternoons (while the more famous undergraduate Lectures on Physics were given in the mornings), they require a high level of mathematical maturity. Feynman Lectures on Gravitation - IOPscience Feynman Lectures on Gravitation
: He treats gravity like other fundamental forces, using tools from quantum electrodynamics (QED) and particle physics. The 16 lectures cover a wide range of