Blackstone's culture begins with silver-haired founders Pete Peterson and Stephen Schwarzman, who are no strangers to youthful ambition. As Peterson's young protégé at Lehman, Schwarzman became a managing director at by age 31. Unsurprisingly, the firm they built together holds even its youngest associates to a very high standard and rewards them with great responsibility. Hire the best, enforce a meritocracy, and actively manage the tendency to overachieve. "A starting level person fails by taking on too much, and then not delivering," says Schwarzman. "We encourage asking for help rather than pretending that all is fine."