Contents: (1) Introduction. (2) Resonant cavities in the Sun. (3) Observational methods. (4) High-degree modes: Solar structure. Subphotospheric velocities. (5) Low-degree modes: High-order p modes. Gravity modes. Solar structure. (6) Five-minute modes of intermediate degree. (7) Limb observations. (8) Problems for the immediate future. Appendix: Classification of stellar oscillations.