What have we learnt about B-type stars from their pulsations?

High-precision space observations have revolutionized our knowledge about many pulsators. For example, it appeared that in most (if not all) B-type pulsating stars both pressure (p) and gravity (g) modes are observed, i.e., they are hybrid pulsators of $\beta$ Cep/SPB or SPB/$\beta$ Cep type. This discovery has opened up a possibility of getting more stringent constraints on parameters of the model and theory because a simultaneous excitation of p and g modes offers probing stellar regions sensitive to various physical processes. On the other hand, the presence of high order g-modes in $\beta$ Cep stars and p modes in SPB stars is a challenging fact waiting for explanation because these modes are stable in all standard opacity models. In this talk, we present the main results obtained from seismic studies of B-type main sequence pulsators. In particular, we discuss seismic constraints obtained for convective overshooting, internal rotation and stellar opacities.