Black Holes as Dark Matter

The possibility that some of the black holes in the universe have a non-stellar origin and that they play a significant role in cosmology - including being some or all of the dark matter - is both timely and intriguing. I will review the status of the field, describe search strategies and future prospects for detection across many decades in mass, discuss how primordial black holes could seed both baryonic and particle dark matter in the very early universe, and argue that the search for sub-solar mass black holes may lead to a deeper understanding of the elusive Galactic "rogue planets".