Abstract
A pulsating star can reveal a good deal of its structure to one who can understand the eigen modes it produces. However, it is surprising to realise that, in most of the cases, one who knows about eigen modes do not know why the star is pulsating at first!
The GW Vir stars are a rare exception to that rule. We understand the driving mechanism responsible for their vibrations from the beginning of their instable life to their return as simpler, stable white dwarfs. In this presentation, I review the roots of this understanding. I also show how the hot and vibrating GW Vir stars are great laboratories to test our knowledge of stellar astrophysics.