Here's a 2003 gem from The Atlantic on introverts (via @smc90). I hire a lot of introverts. They make great copy editors. The hard part is getting them past the newsroom extroverts in the interview gantlet.
Introverts are not necessarily shy. Shy people are anxious or frightened or self-excoriating in social settings; introverts generally are not. Introverts are also not misanthropic, though some of us do go along with Sartre as far as to say "Hell is other people at breakfast." Rather, introverts are people who find other people tiring. Extroverts are energized by people, and wilt or fade when alone. They often seem bored by themselves, in both senses of the expression. Leave an extrovert alone for two minutes and he will reach for his cell phone. In contrast, after an hour or two of being socially "on," we introverts need to turn off and recharge. My own formula is roughly two hours alone for every hour of socializing. This isn't antisocial. It isn't a sign of depression. It does not call for medication. For introverts, to be alone with our thoughts is as restorative as sleeping, as nourishing as eating. Our motto: "I'm okay, you're okay—in small doses."