Most planet searches focus on single stars, like the sun. But half of all sun-like stars actually live in binary or multiple stellar systems, whose planet-hosting capability may be quite different. In binary systems, planets can occupy either circum-stellar or circum-binary orbits, but many orbital configurations are thought to be unstable due to the effects of the binary companion. Binaries are also thought to affect the proto-planetary disks of their companions, potentially disrupting their ability to form planets at all.