Astrophysical Lessons from Gravitational-wave Catalogs

I will describe some recent results on the binary black hole population, including the mass distribution, the spin distribution, and evolution with redshift. I will highlight some features in the population distributions, including gaps in the mass distribution, the spins of binary black holes compared to black hole X-ray binaries, and the time delays that black holes experience between formation and merger. I will summarize some astrophysical interpretations of these population properties and what we expect to learn from future observations.