  I discuss the structure and composition of massive (two solar-mass) neutron
stars containing hypernuclear and deconfined quark matter in color
superconducting states. Stable configurations featuring such matter are
obtained if the equation of state of hadronic matter is stiff above the
saturation density, the transition to quark matter takes place at a few times
the nuclear saturation density, and the repulsive vector interactions in quark
matter are substantial. I also discuss our recent progress in understanding the
cooling of massive compact stars with color superconducting quark cores.
