Nobody quite knows where Humans originated from, or how they came to be spread across a million worlds. Their homeworld is unknown, obscured by the foggy depths of time, though some notable Imperial xenoarchaeologists have speculated that the species may have originated on Coruscant, hence the planet's continued dominance in galactic trade and as the governmental seat of power, both under the Old Republic and as it is now, under the Empire. This explanation has been rejected by the Rebel Alliance, believing it to be Imperial Propaganda, in a vain and thinly veiled attempt at ratifying the Emperor's anti alien bias.
Humans have always played a prominent part in the development of the galaxy and in galactic politics, not least because of the Empire's hatred of non-human races. Though there are many planets in the galaxy which are generally populated only by Humans, such as the Corellians and the Alderaanians, there are no biological differences between them. They can be found anywhere, engaged in many different pursuits: Mercenaries, pilots, smugglers, merchants, Imperial recruits, assassins, farmers, crime lords, labourers and many others.
Humans are also naturally attuned to the Force, turning out more Force sensitive and Force users than any other species, with the possible exception of the Gand. Many famous Jedi, both of the Old Republic and under the Empire and the Alliance, were Human.