Not yet reviewed by Pith; the record is open.

We consider dissipative atom-cavity systems and show that their collective dynamics leads to the maximization of entanglement for intermediate values of the cavity leakage parameter $\kappa$. We discuss possible ways the reservoir influences entanglement. We first consider the entanglement of a single two-level atom with a microwave cavity that is coupled to another cavity. We show that the atom-cavity entanglement can be made to increase with cavity leakage. We next show that the entanglement between two atoms passing successively through a cavity can be maximised for intermediate values of $\kappa$. We finally consider the micromaser where the increase of two-atom entanglement for stronger cavity-environment coupling is demonstrated for experimentally attainable values of the micromaser parameters.