The Andromeda Galaxy, M31, is our nearest large galaxy. At a distance of 2.9 million lightyears, the galaxy is one of the chief items in the "Local Group" of galaxys, of which our own is part.
Andromeda can be easily glimpsed by the naked eye under even moderate viewing conditions. The Persian astronomer, Al-Sufi, referred to M31 as "the little cloud." The first telescopic description of M31 is credited to Simon Marius in 1612. Andromeda is easily the most studied galaxy because it allows us to observe features of our own Milky Way galaxy from the outside.
