Elon Musk is a body that remains very much in motion.

By the time this book reaches your hands, it's quite possible that Musk and SpaceX will have managed to land a rocket on a barge at sea or back on a launchpad in Florida. Tesla Motors may have unveiled some of the special features of the Model X. Musk could have formally declared war on the artificial intelligence machines coming to life inside of Google's data centers. Who knows?

What's clear is that Musk's desire to take on more keeps growing. Just as I was putting the finishing touches on this book, Musk unfurled a number of major initiatives. The most dramatic of which is a plan to surround the Earth with thousands of small communications satellites. Musk wants, in effect, to build a space-based Internet in which the satellites would be close enough to the planet to beam down bandwidth at high speeds. Such a system would be useful for a couple of reasons: In areas too poor or too remote to have fiber-optic connections, it would provide people with high-speed Internet for the first time. It could also function as an efficient backhaul network for businesses and consumers.

Musk, of course, also sees this space Internet as key to his long-term ambitions around Mars. "It will be important for Mars to have a global communications network," he said. "I think this needs to be done, and I don't see anyone else doing it." SpaceX will build these satellites at a new factory and will also look to sell more satellites to commercial customers as it perfects the technology. To fund part of this unbelievably ambitious project, SpaceX secured $1 billion from Google and Fidelity. In a rare moment of restraint, Musk declined to provide an exact delivery date for his space Internet, which he forecasts will cost more than $10 billion to build. "People should not expect this to be active sooner than five years," he said. "But we see it as a long-term revenue source for SpaceX to be able to fund a city on Mars."

Meanwhile, SolarCity has purchased a new research and development facility near the Tesla factory in Silicon Valley that's intended to aid its manufacturing work. The building it acquired was the old Solyndra manufacturing plant -- another symbol of Musk's ability to thrive in the green technology industry that has destroyed so many other entrepreneurs. And Tesla continues to build its Gigafactory in Nevada at pace, while its network of charging stations has saved upward of four million gallons of gas. During a quarterly earnings announcement, J. B. Straubel promised that Tesla would start producing battery systems for home use in 2015 that would let people hop off the grid for periods of time. Musk then one-upped Straubel, bragging that he thinks Tesla could eventually be more valuable than Apple and could challenge it in the race to be the first $1 trillion company. A handful of groups have also set to work building prototype Hyperloop systems in and around California. Oh, and Musk starred in an episode of The Simpsons titled "The Musk Who Fell to Earth," in which Homer became his inventive muse.

The heady expansion plans and triumphant rhetoric from Musk were still not quite enough to hide all of Musk Co.'s flaws. Early 2015 marked the vociferous return of Musk's detractors on Wall Street. Tesla's sales in China were lackluster by any measure, and some analysts renewed their doubts about how much long-term demand there would be for the Model S. Tesla's shares slumped and, for the first time in a while, Musk sounded flustered trying to defend the company's position.

The personal costs of Musk's lifestyle were more severe. Musk announced that, once again, he would be divorcing Talulah Riley. According to Musk, Riley wanted a simpler, smaller life in England and had come to despise Los Angeles. "Tried to talk her out of it, but she insisted," Musk told me. "It is possible that she will change her mind at some point, but not anytime soon."

After finishing my reporting and writing for this book, I had a chance to speak with some of Musk's confidantes and employees in a more relaxed manner and bounce various ideas off of them. I'm more convinced than ever that Musk is, and has always been, a man on a quest, and that his brand of quest is far more fantastic and consuming than anything most of us will ever experience. It seems that he's become almost addicted to expanding his ambitions and can't quite stop himself from announcing things like the Hyperloop and the space Internet. I'm also more convinced than ever that Musk is a deeply emotional person who suffers and rejoices in an epic fashion. This side of him is likely obscured by the fact that he feels most deeply about his own humanity-altering quest and so has trouble recognizing the strong emotions of those around him. This tends to make Musk come off as aloof and hard. I would argue, however, that his brand of empathy is unique. He seems to feel for the human species as a whole without always wanting to consider the wants and needs of individuals. And it may well be the case that this is exactly the type of person it takes to make a freaking space Internet real.