About a million quasars have been identified with reliable spectroscopic redshifts, and between 2-3 million identified in photometric catalogs. The nearest known quasar is about 600 million light-years from Earth. The record for the most distant known quasar continues to change. In 2017, quasar ULAS J1342+0928 was detected at redshift z = 7.54. Light observed from this 800-million- solar-mass quasar was emitted when the universe was only 690 million years old. In 2020, quasar Pōniuāʻena was detected from a time only 700 million years after the Big Bang, and with an estimated mass of 1.5 billion times the mass of the Sun. In early 2021, the quasar QSO J0313–1806, with a 1.6-billion-solar-mass black hole, was reported at z = 7.64, 670 million years after the Big Bang.