I'd often thought of nostalgia as a basic part of the human condition. Some people are more nostalgic than others, but I thought it was an illness rooted in the human experience of time - an effect not just of memory and aging, but a wish that a moment of life was not so ephemeral.
The text below from the Straight Dope brings that into question.
We get nostalgic for Victorian Christmases. What did Victorians get nostalgic for?
... to paraphrase musical philosopher Dan Hicks, you can't miss it if it won't go away. Nostalgia, like Rice Chex, antacid tablets, and Dan Rather, is a product of modern urban industrial society, which is continually assaulted by change (AKA progress, for the optimists among us) and where most people have lost their sense of connection to the land. In a traditional agricultural society there's nothing to get nostalgic about, since you're still living on the land and yesterday was pretty much the same as today.
Longing for the past dates from the early 19th century, not long after the start of the industrial revolution in England. (The word nostalgia wasn't widely applied to said longing until after World War I, having previously signified a pathological case of homesickness.) Early promoters of nostalgia included the poet William Wordsworth and the novelist Sir Walter Scott, whose novel Ivanhoe (1819) launched a fad for chivalry. Romantic literature appealed to city folk, now a bit disenchanted with urban life (as the philosophes of a previous generation had not been) and thus inclined to a sentimental view of the lost joys of nature, childhood, and the past.