Physics and gas dynamics of wind-blown bubbles

We review the recent hydrodynamic modelling of wind-blown bubbles (WBB) whi ch are result of interaction of a stellar wind with the circumstellar matte r or the wind(s) emitted during the previous stages of the central star evo lution. The much faster computers becoming available in the last decade all ow a more complete picture of the physics of these objects to be built. Rec ent hydrodynamic models are capable of treating in detail different mechani sms as radiative plasma cooling, electron thermal conduction and the effect s of magnetic fields. We discuss the various mechanisms proposed for shapin g these objects and we emphasize on the problems related to the development of various instabilities and the X-ray emission from WBB.