Baby Zuckerberg has arrived. Mark Zuckerberg and Priscilla Chan welcomed their new baby girl, Max, to the world Tuesday afternoon. Along with the announcement of her birth came a letter to Max from the new parents. Included was the announcement that Zuckerberg will donate 99 percent of his Facebook shares, valued at $45 billion.

Dear Max,

Your mother and I don't yet have the words to describe the hope you give us for the future. Your new life is full of promise, and we hope you will be happy and healthy so you can explore it fully. You've already given us a reason to reflect on the world we hope you live in.

Like all parents, we want you to grow up in a world better than ours today.

While headlines often focus on what's wrong, in many ways the world is getting better. Health is improving. Poverty is shrinking. Knowledge is growing. People are connecting. Technological progress in every field means your life should be dramatically better than ours today.

Zuckerberg has been leading and growing Facebook, the online social network that now connects over 1.55 billion people every month. Now, he wants his daughter to help understand the world he has helped shape. In a letter of over 2,000 words, which Zuckerberg publicly shared on Facebook, he and his wife discussed many challenges the world currently faces and encouraged their daughter to act -- and to give.

"By partnering with schools, health centers, parent groups and local governments, and by ensuring all children are well fed and cared for starting young, we can start to treat these inequities as connected. Only then can we collectively start to give everyone an equal opportunity," the letter reads.

But Zuckerberg did not just write about giving in the future. The letter also announced Zuckerberg's intention to give away 99 percent of his Facebook shares, which are currently valued at $45 billion, to help improve many areas of life, focusing on "personalized learning, curing disease, connecting people and building strong communities." He already filed an 8-K form with the Securities and Exchange Commission announcing his intention. 

"On December 1, 2015, our founder, chairman and CEO, Mark Zuckerberg, announced that, during his lifetime, he will gift or otherwise direct substantially all of his shares of Facebook stock, or the net after-tax proceeds from sales of such shares, to further the mission of advancing human potential and promoting equality by means of philanthropic, public advocacy, and other activities for the public good," the filing reads

His strategy for giving away the stock, according to the filing, includes donating $1 billion each year for the next three years. The filing also clarifies that Zuckerberg plans to retain his majority voting position "for the foreseeable future."

Zuckerberg and Chan's decision received the praise of Facebook Chief Operating Officer Sheryl Sandberg. "From the moment I met Mark and Priscilla I knew they would change the world. Their decision to invest now in the future is smart and important – it will fund the kind of work that no-one else will," Sandberg wrote in a post on her personal Facebook page.

Those funds will help support the Chan Zuckerberg Initiative, a new incorporated LLC, which has a mission to "advance human potential and promote equality in areas such as health, education, scientific research, and energy," according to its official Facebook page. 

Zuckerberg will now take two months of paternity leave, a decision he announced last month. Facebook recently expanded its own paternity and maternity leave policy to full-time employees outside the U.S. The company offers four months of paid leave, which employees may use at any point up to a year after the child's birth.