Here's a
very brief sysnopsis of 'How Humans from Earth are Aliens in Traveller'
300,000 years ago a race called the Ancients visited Earth and took with them sample of Homo Sapiens as slave/workers/whatever. The Ancients empire was destroyed in a star-spanning war but the humans they brought with them survived in small (initially) isolated pockets. There are/were 46 different sub-species of humans now in existance as each pocket of humanity adapted to its new home.
One of these races, the Vilani, created the first Imperium of the galaxy about 10,000 years before the Terrans of Sol (also called the Solomani) first developed the star drive. The Vilani Empire came into bloody conflict with the Terran Confederation (as the Solomani called their fledgling empire) in -2242 (meaning 2242 years before the start of the Third Imperium which currently counts at year 1110) and hastened the Vilani's demise (it had been in slow decay for many decades at that point).
The Solamani, however, failed to stop the technological collapse called the Long Night. the Long Night was really the inevitable result of the oppressive rule of the Vilani and the 200 year war with the Solomani and (brief) Rule of Man lead to the near complete collapse of any sort of infastruture linking the many worlds and trillions of people of the galaxy.
The Long Night lasted from -1776 to Year 1 of the Third Imperium (which began with Cleon I on Sylea). It wasn't until 588 that Terra joined the 3rd Imperium and by 990 it was in open warfare with the rest of the Imperium. The Solomani never had much of a chance against the might of the Imperium and were defeated in 998 with the defeat and occupatiob of Terra itself by victorious Imperial forces. By this point the Imperium occupied nearly 1/3 of the Solomani's old expanses and this is considered the end of the Solomani Confederation.
Thus since any PCs are considered to be from the Imperium (at least in classic Traveller) any Solomani persons are considered 'alien' in that they were late comers to the Imperium and have actually fought a war against Imperial interests.
I always loved this setting (can you tell

?) and it even borrows some of my favourite elements from my favourite authour H. Beam Piper (specifically the formation of the Sword Worlds from the humans of Terra).
I am sooooooo pumped about this new book - any info on when it hits stores?