Nonequilibrium steady state behavior in driven, open quantum systems has generated significant interest in recent years. I will discuss certain aspects of dissipation and decoherence in quantum systems, leading to the emergence of the Kraus map and the GKLS (“Lindblad”) Master equation. Under GKLS dynamics, the density matrix for boundary driven quantum systems - for example, a chain coupled to different heat baths at either end - relaxes to a nonequilibrium steady state (NESS), the properties of which depend on whether the bulk Hamiltonian is integrable or not. For the nonintegrable case, the NESS is found to obey a generalization of the Eigenstate Thermalization Hypothesis for isolated quantum systems.