  These lecture notes are intended for starting PhD students in theoretical
physics who have a working knowledge of General Relativity. The 4 topics
covered are (1) Surface charges as conserved quantities in theories of gravity;
(2) Classical and holographic features of three-dimensional Einstein gravity;
(3) Asymptotically flat spacetimes in 4 dimensions: BMS group and memory
effects; (4) The Kerr black hole: properties at extremality and quasi-normal
mode ringing. Each topic starts with historical foundations and points to a few
modern research directions.
