The 16 lectures cover a wide range of advanced theoretical physics, including:
: He posits the existence of a massless particle with spin 2 and derives the consistency requirements that lead directly to the non-linear Einstein field equations. Feynman Lectures on Gravitation
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 The 16 lectures cover a wide range of
: Early attempts and challenges in unifying gravity with quantum mechanics, highlighting the fundamental difficulties of low-energy quantum gravitational field theories. Study Guide Recommendations the necessity of a tensor field
: The principle of equivalence, the necessity of a tensor field, and the iterative derivation of field equations.