Progress and problems in massive star pulsation theory

Massive stars pulsate in various modes; radial and nonradial p-modes, g-modes, and strange modes including oscillatory convective (non-adiabatic g^-) modes. Those modes are responsible for the light and velocity variations of β Cephei stars, slowly pulsating B (SPB) stars, and α Cyg variables. The instability mechanisms for these pulsations are discussed. We also discuss the relation between the evolution of massive stars and the excitation of strange modes, which are considered responsible for the pulsation in most of the α Cyg variables. The surface He and CNO abundances of hotter α Cyg variables seem to indicate that the Ledoux criterion of convection is better than the Schwarzschild criterion, although the latter is extensively used in stellar evolution computations.