Apple launched iPhone 4S at a news conference in Los Angeles on Oct 4, 2011. A highlight of that news conference was the promotion of a new function-the artificial intelligence voice assistant Siri, and it was one of the last projects Steve Jobs had a hands-on involvement with at the company. An empty seat at the event was seen marked as "reserved "for Jobs, though he was unable to appear.

One day later, the news about Jobs' death shocked the world, and Tim Cook, who had only been Apple's CEO for over a month at Jobs' request, was thrust into the spotlight. People wondered how Cook would fill the space left by Apple's iconic former leader.

This is among the subjects addressed in a biography of Cook, which was published in April, and now has a Chinese version, published in June by China CITIC Press. Written by journalist Leander Kahney, Tim Cook: The Genius Who Took Apple to the Next Level clarifies what Cook has done, his values, his management of Apple and his growth experience.

Kahney has covered the tech giant for more than two decades and now works as an editor at Cult of Mac, a site that covers everything related to Apple. He has written four best-selling books about the company, including Jony Ive: The Genius Behind Apple's Greatest Products, Inside Steve's Brain, Cult of Mac, and Cult of iPod.

This time, Kahney interviewed a number of Apple executives and members of Apple's public relations team and referred to many reports about Cook in order to write this book. "When Cook took over from Jobs, a lot of Apple pundits predicted doom, but the fact proves that he was growing Apple to be even bigger and more influential than it had ever been. I want to document that," Kahney writes in an email interview to China Daily.

According to Han Xiao, the editor of this book at China CITIC Press, "We are introducing this book in China because it suits our product line to publish biographies of businesspeople, the author is famous enough to write about Apple and it's a continuation since we have published biographies of Steve Jobs and Apple's chief design officer Jony Ive."

From the book, we can see that people's worries have almost disappeared in recent years, especially since "Apple reached the ultimate milestone, becoming the world's first trillion-dollar company" under Cook's leadership, writes Kahney in the book.

People doubted Cook because he is so different from Jobs. Jobs was charming, a visionary, full of leadership and personality skills, while Cook is introverted, mild and keeps a low profile, according to the author.

"Jobs was a great product guy, and a gambler. He'd risk everything on new, untested products, and was often right. However, he had little patience or interest in the day-to-day running of a company, while Cook is much better at execution. The skills and strengths of Jobs and Cook complement each other perfectly and lead to the giant that Apple is today," explains Kahney.