Shortly after signing on as chief operating officer at Facebook, Sheryl Sandberg was looking to connect with people in a similar role - No. 2 to a brilliant and passionate young founder. She called Tim Cook.
"He basically explained nicely that my job was to do the things that Mark (Zuckerberg) did not want to focus on as much," Sandberg said of the 2007 meeting that lasted several hours with the chief operating officer of Apple Inc.
"That was his job with Steve (Jobs). And he explained that the job would change over time and I should be prepared for that."
While Sandberg has enjoyed a steady run at Facebook, it is Cook's job that has changed radically since then. Now, the man who was handed one of the more daunting tasks in business - filling the shoes of the late Steve Jobs and keeping Apple on top - may himself need a spot of advice.
Two years into Cook's tenure, Apple is expected to unveil a redesigned iPhone next month. It will be a key moment for Cook. The company he inherited has become a very different creature: a mature corporate behemoth rather than a scrappy industry pioneer, with its share price down 5 percent this year, despite a recent rally. The S&P 500 is up about 15 percent this year.
A transition was, perhaps, inevitable after an astonishing five-year run in which Apple's headcount tripled, its revenues rose over six-fold, its profits grew 12-fold, and its stock price jumped from $150 to a peak of $705 last fall.
But it's been painful for some.
It is unclear whether the spread-sheeting-loving, consensus-oriented, even-keeled Cook can successfully reshape the cult-like culture that Jobs built. Though Cook has deftly managed the iPhone and iPad product lines, which continue to deliver enormous profits, Apple has yet to launch a major new product under Cook; talk of watches and televisions remains just that.
Some worry that Cook's changes to the culture have doused the fire - and perhaps the fear - that drove employees to try to achieve the impossible.
CAN NICE GUYS FINISH FIRST?
Cook is known as a workaholic who guards his privacy closely. People who know him well paint a portrait of a thoughtful, data-driven executive who knows how to listen and who can be charming and funny in small group settings.
Lisa Cooper, who went to high school with Cook in Robertsville, Alabama, and remains a friend, still laughs at memories of Cook staging prank photos for the school yearbook and crooning "The Way We Were" to her in class.
In the day to day at Apple, Cook has established a methodical, no-nonsense style, one that's as different as could be from that of his predecessor.