This lecture covers the Hartree-Fock method in quantum chemistry, focusing on basis sets, Slater determinants, and the Born-Oppenheimer approximation. It explains the concepts of spin contamination, self-consistent field methods, and the importance of basis set superposition error. The instructor discusses the justification of Hund's rule based on the Hartree-Fock energy expression and the different types of Hartree-Fock calculations. Practical warnings and exam details are also provided.