The Wall Street Journal has included an excerpt from the soon-to-be-published book The Genius in All of Us: Why Everything You've Been Told About Genetics, Talent, and IQ Is Wrong. From "The Success Myth":
...It would be folly to suggest that anyone can literally do or become anything. But the new science tells us that it's equally foolish to think that mediocrity is built into most of us, or that any of us can know our true limits before we've applied enormous resources and invested vast amounts of time. Our abilities are not set in genetic stone. They are soft and sculptable, far into adulthood (as documented well in Sharon Begley's recent book "Train Your Mind, Change Your Brain"). With humility, with hope, and with extraordinary determination, greatness is something to which any kid—of any age—can aspire. The better we understand what greatness is really made of, the more of it we can grasp—as individuals, as families and as a talent-promoting society.
Note (added March 8, 2010): A review of the book: "The Genius in All of Us" (New York Post). From that review:
When witnessing an awe-inspiring talent, whether it comes from sports, music or literature, most people just chalk it up to natural-born gifts. While discussing arguably the greatest baseball hitter ever, Ted Williams, plenty of knowledgeable fans remark that he had superhuman eyesight, allowing him to see the ball’s release point and rotation better than anyone else.
What they don’t mention nearly as often is that the Red Sox legend conditioned himself to see the ball better by spending countless hours perfecting his swing. As journalist Shenk points out, Williams practiced until his hands bled and would walk down the street with one eye closed in order to strengthen his vision.