The portrait of Paul Allen on the cover of his new memoir, Idea Man, captures the Allen we know and the Allen we don't. He resembles a Photoshopped version of the real man, a waxen Madame Tussauds figure that embodies the awkwardness of a very private person going public, one eager for recognition yet uncomfortable in the public eye.

Live sightings of Allen are rare: He lives in a private island compound, he travels the world by private jet and mega-yacht (even he, he says, was shocked at the size of his magnificent ship Octopus when he first saw her, seven stories high and much longer than a football field). He's been to the Arctic and Antarctic, and to the depths of the ocean in his private submarine. A favorite haunt seems to be East Africa, with recent trips to Botswana.

He's hard to pin down, in physical space as well as his defining characteristics. That was one reason, I think, that Seattle packed Town Hall on Friday (April 22) to see Allen on stage for an interview with Geekwire blogger Todd Bishop. For many, a globetrotting billionaire Bigfoot had finally agreed to a sit-down.

A first impression: Allen is taller than you think, though he often towered over Bill Gates in old photos from their early years of partnership when Allen looked like a long-haired hippie patriarch with Gates, who well into his 20s resembled a tween nerd from the Disney Channel. Allen is shaven now, slender of face and neck, the middle-age paunchiness has slipped lower down, couch-potato style. He is a remarkably unremarkable-looking man, a bit like you'd imagine the town pharmacist might have looked in his parents' hometown of Anadarko, Oklahoma.

What is striking are his hands, and how he talks with them. They are intense, the fingers long. You can see the young programmer's drive coming through them, as if the points he is making emanate from his fingertips. Allen says that he uses a BlackBerry because he has "really fast thumbs" and his mother trained him to touch-type. But they are also the hands that can finesse a basketball through the hoop playing HORSE with members of the Portland Trailblazers, or that have helped him try to experience what it was like to be Jimi Hendrix by playing his electric guitar late into the night and, later, rocking with Jagger and Bono. The hands reveal a Paul Allen whose soft figure and bland exterior contain no softy. The hands seem to possess his life force.

Which is strong, after two bouts of cancer (both Hodgkin's and non-Hodgkin's lymphoma) and a weakened heart (he has a pacemaker). His book Idea Man was driven by his worry that cancer would cut his life short before he'd had a chance to tell his story. He says working on it helped him through a year of chemo and recovery, but it is clear that he was driven to beat the reaper after a middle-age wakeup call. For a man who appears comparatively quiet, he has a lot to talk about.

Allen considers himself a generalist, and also a man of creative powers who "thinks in the future tense." It has been more than a quarter of a century since Allen left Microsoft in the early '80s, though he did later serve on its board. That made his fortune, but his interests in riding the tech wave and plowing his fortune into innovative ventures is really driven by a desire to change the world. More than perhaps anyone, Allen was inspired by the Seattle World's Fair's science exhibits (particularly the Federal Science Pavilion, now the Science Center). And he internalized its message that science and technology were key to progress. Allen loves music, reading, he collects great art, but if his interests are wide-ranging, his true passion is in research and development. Allen is the ultimate progeny of the Sputnik moment.

He also has absorbed the middle-class dedication to self-improvement inculcated in boomers by their Greatest Generation parents (Allen's father, a WWII vet who never talked much about the war, was a library administrator at the University of Washington, his mother a school teacher and inveterate reader). Allen calls himself just a "boy from North Seattle" — Wedgwood to be exact — and his memoir reveals that his life has been steered by earnest PBS programming. It was Carl Sagan, whose "Cosmos" Allen loved, who convinced him to financially support the search for extraterrestrial life by monitoring galactic radio signals with what is now the Allen Array of satellite dishes. His love of scuba diving and personal deep-sea exploration came courtesy, he says, of Jacques Cousteau's documentaries.

Pop culture, too, plays a big role in shaping Allen's pursuits: His boyhood love of science fiction led to an interest in rocketry and the Allen-backed Space Ship One, not to mention a science-fiction museum. His love of rock produced EMP and an obsession with Hendrix. He was delighted to pay $750,000 for Hendrix's Woodstock Stratocaster in 1991, and Great Recession hindsight doesn't seem to have changed his view. Allen's passion for music and his eclecticism come from a genuine excitement ignited by art, science, movies, and TV programming we all encountered, but Allen has had the resources to follow up, to embrace them personally, to fund research that can take ideas to the next level.

EMP, for example, is justified as not simply a tribute to music and the creative spirit, but as a place that just might inspire the next Hendrix through exposure to sounds and instruments. Allen also donated millions to the UW for the Allen Library. He has a great interest in the future of teaching science, and his Halo Project is trying to program a machine to teach college-level biology, an extremely complex programming challenge. It's nothing less, he says, than a Digital Aristotle. I hear in Allen the echo of my own parents, of the same generation and class as his, of having the obligation to use one's mind and creativity to "make the world a better place," in part by improving yourself in secular, non-material ways, especially through science and art.

Allen's greatest indulgence, it seems to me, is commendable: giving free reign to his intellectual curiosity. Sometimes it seems like he's channeling a combination of Carl Sagan and Jules Verne, but the point is he's out there putting his money where his interests are, and his book is largely devoted to telling us what those are.

Having now read the entire book, I am struck by a couple of things. One is that while much attention has focused on the hard things he said about Bill Gates, the book is more nuanced. Not that Allen is backing off any claims of Gates' cruelty and greed along the way. He told the Town Hall audience that no one has challenged any of his facts though they might have a different opinion about them. He and Gates hadn't talked yet by then, but Allen and Microsoft boss Steve Ballmer have been talking. Allen recognizes that his partnership with Gates, forged in their early teens, was unique and formed a strong bond.