Future History

Future History is the name commonly given to the series of books and short stories by Robert Heinlein, one of the greatest Science Fiction authors of all time.

Eventually, all of Robert Heinlein's books were tied into this series, which began with the story "Methuselah's Children" and the wonderful character of Lazarus Long, the oldest member of the human race. Highly recommended reading.

Methuselah's Children isn't the beginning of Heinlein's Future History; it's merely the first appearance of Lazarus Long in it. There were quite a lot of stories establishing that universe -- they are mostly collected in the anthology The Past Through Tomorrow, which comes before the related novels.

Perhaps the most impressive example of Future History are the books of Isaac Asimov whose 'Galactic Saga' takes up around a yard of well spent shelf space and runs from the 1980s to (if I've worked it out right) 25621AD. A timeline is available here.

Another interesting Future History was created by the Fading Suns series of books and games. An account of this Future History is here