Facebook CEO Mark Zuckerberg turned 28 on Monday, kicking off what's set to be the biggest week in his social network's eight-year history. The company is preparing to launch its initial public offering on Friday, and the IPO is expected to value Facebook at a stratospheric $100 billion, more than McDonald's, Goldman Sachs, and dozens of other venerable companies. Investors are questioning whether Zuckerberg is mature enough to run a publicly traded company, and whether he can thrive under the ruthless glare of Wall Street. In pursuit of that question, The New York Times looks for answers from those closest to him in a new investigative report, for which Zuckerberg himself declined to be interviewed. Here, four revealing tidbits:

1. Empire-building is in Zuckerberg's bones
Zuckerberg isn't interested in selling the company and making a quick buck. As a boy, his "favorite video game was Civilization, the object of which is to 'build an empire to stand the test of time,'" say Evelyn M. Rusli, Nicole Perlroth, and Nick Bilton at The Times. A childhood friend says Civilization served as "training wheels" that helped Zuckerberg prepare to run Facebook.

2. He counts Bill Gates among his mentors 
Zuckerberg has cultivated a "personal brain trust beyond" Facebook that includes Microsoft founder Bill Gates, Netscape co-founder Mark Andreessen, Washington Post CEO Donald Graham, and, while he was alive, former Apple CEO Steve Jobs. Zuckerberg was so intent on meeting Gates that he asked a venture capitalist back in 2005 not only to invest in Facebook, but to arrange an introduction. The meeting didn't come off, but Zuckerberg eventually met Gates on his own, and regularly turns to him for advice on "philanthropy and management issues."

3. Zuck can handle big acquisitions on his own 
When Zuckerberg wants to buy a company, he likes to negotiate sans lawyers, says The Times. In the run-up to Facebook's $1 billion purchase of the photo-sharing app Instagram earlier this year, Zuckerberg reportedly reached a deal with Instagram chief Kevin Systrom in private. Zuckerberg and Systrom finalized the acquisition over steaks and ice cream, while the lawyers sat on the couch watching the HBO series Game of Thrones.

4. He's well aware of his own weaknesses
Beneath his customary hoodie "is an increasingly assured leader, one tempered by failures — and there have been some big ones — as well as astonishing successes," say Rusli, Perlroth, and Bilton. Zuckerberg focuses on his strengths in product design and strategy, while delegating tasks at which he is weak — day-to-day management and operation — to people with more experience in those areas. "Like a software engineer writing a program, he has tried to fill in the gaps in his personal code, and to ensure, as a programmer might put it, that his code doesn't break."

Read the entire article at The New York Times.