An in-depth exploration of major topics in organic chemistry, emphasizing physical principles over synthesis. Themes will include the detailed consideration of molecular structure, including of unusual and theoretically important molecules; the interpretation and elucidation of reaction mechanisms; thermodynamic and kinetic approaches to understanding reactivity; and quantitative approaches to all of the preceding. The course will also examine qualitative molecular orbital theory, as well as provide a brief introduction to computational electronic structure methods. In general, the goal will be to continue the study of organic chemistry from where the Chemistry 22/32 sequence ends.