And John Archibald Wheeler - Gravitation By Charles W. Misner Kip S. Thorne

The core: Riemann tensor, Bianchi identities, Einstein equation. Pay special attention to Box 14.5 (derivation from action principle).

Classic material: photon sphere, event horizon, Eddington–Finkelstein coordinates. Their discussion of “river model” of black holes is unique. The core: Riemann tensor

Quadrupole formula, TT gauge, energy flux. Still a benchmark. energy flux. Still a benchmark.