'This is not goodbye': Tim Cook reflects on 15-year journey at Apple; read full letter here

Apple said Monday that Tim Cook, its longtime CEO, would step down in September, handing the top job to company veteran John Ternus.

Cook said he will become executive chairman of the board when he cedes Apple's CEO position.

"It has been the greatest privilege of my life to be the CEO of Apple and to have been trusted to lead such an extraordinary company," Cook said in a statement.

Cook joined Apple in 1998, rising through the ranks and helping drive its success as chief operating officer coordinating the iPhone maker's complex supply chain.

He became chief executive in 2011 after its iconic co-founder and leader Steve Jobs left due to health issues.

In a letter addressed to the Apple community, Cook recalled his journey at Apple. "For the past 15 years I’ve started just about every morning the same way. I open my email and I read notes I received the day before from Apple’s users all over the world."

He wrote, "In every one of those emails I feel the beating heart of our shared humanity. I feel a sense of deepening obligation to work harder and push further. But most of all, I feel a gratitude that I cannot put into words, that I somehow got to be the person on the other end of those emails, the leader of a company that ignites imaginations and enriches lives in such profound ways it defies description. What an honor and a privilege it has been."

Read Tim Cook's full letter here:

To the Apple community:

For the past 15 years I’ve started just about every morning the same way. I open my email and I read notes I received the day before from Apple’s users all over the world.

You share little pieces of your lives with me and tell me things you want me to know about how Apple has touched you. About the moment your mom was saved by her Apple Watch. About the perfect selfie you captured at the summit of a mountain that seemed impossible to climb. You thank me for the ways Mac has changed what you can do at work and sometimes give me a hard time because something you care about isn’t working like it should.

In every one of those emails I feel the beating heart of our shared humanity. I feel a sense of deepening obligation to work harder and push further. But most of all, I feel a gratitude that I cannot put into words, that I somehow got to be the person on the other end of those emails, the leader of a company that ignites imaginations and enriches lives in such profound ways it defies description. What an honor and a privilege it has been.

Today we announced that I’m taking the next step in my journey at Apple. Over the coming months I will be transitioning into a new role, leaving the CEO job behind in September and becoming Apple’s executive chairman. A new person will be stepping into what I know in my heart is the best job in the world. That leader is John Ternus, a brilliant engineer and thinker who has spent the past 25 years building the Apple products our users love so much, obsessed with every detail, focused on every possible way we can make something better, bolder, more beautiful, and more meaningful. He is the perfect person for the job.

John cares so much about who we are at Apple, what we do at Apple, who we reach at Apple, and he has the heart and character to lead with extraordinary integrity. I am so proud to call him Apple’s next CEO. This company will reach such incredible heights under his leadership, and you will feel his impact in every bit of delight and discovery that grows out of the products and services to come. I can’t wait for you to get to know him like I do.

This is not goodbye. But at this moment of transition, I wanted to take the opportunity to say thank you. Not on behalf of the company, this time, though there is a wellspring of gratitude for you that overflows inside our walls. But simply on behalf of me. Tim. A person who grew up in a rural place in a different time and, for these magical moments, got to be the CEO of the greatest company in the world. Thank you for the confidence and kindness you’ve shown me. Thank you for saying hi to me on the street and in our stores. Thank you for cheering alongside me when we unveiled a new product or service. Thank you, most of all, for believing in me to lead the company that has always put you at the center of our work. Every day we get up and think about what we can do to make your life a little bit better. And every day, you’ve made mine the best I could have asked for.