For example, a seemingly "quiet "leader in his colleagues' eyes, Cook's management is also very effective. He may not shout at or lambaste others over mistakes like Jobs would, but he can "wear people down through an endless barrage of questions" and "requires incredible amounts of detail from his staff".

According to user Toumingtong on the popular Chinese review site, Douban, "It's the most exciting biography I have read this year. Cook is not a second Jobs, he is only Cook. He leads Apple in his own way and is leading it to a more prosperous future with his own values."

In this book, Kahney describes how Cook steered Apple's development by promoting new functions and products. Additionally, it illustrates Cook's attention to Apple's social responsibilities, such as charity work and environmental protection, among others, some of which were ignored by Jobs, according to the book.

Toumingtong adds: "If I had not read this book, I would never have known how much Cook has done for the environment and diversity (in the company)."

Kahney attributes Cook's efforts at Apple to create "a fairer culture where equality and diversity were championed" to his experience growing up in Robertsdale, a typical small town in the American south, where Cook once said he had seen "some of the worst behavior in terms of discrimination. Behavior that would literally make me sick".

But Kahney also points out that although Cook has made strides in adding more women and people of color to Apple's management, Apple's leadership is still overwhelmingly white and male. "Cook seems sincere in his efforts to change Apple and the wider tech industry, but Apple could and should be doing far more to become more diverse."

Kahney says that most things he has written in this book are positive since he "just reported what he heard" and "could not find many downsides and criticisms" from the interviewees.

"Apple helped me to interview several executives who worked closely with Cook and they were all very complimentary and positive, as were all the ordinary staffers I talked to.

"It's not my job to protect Apple's reputation, and I never approached the book in that way. It's just a product of what I was told while reporting."