When he helped to found Microsoft, Paul Allen changed civilisation.
He ushered in a world of computers and coding, of dizzying development and the relentless power of ever-smaller microprocessors.
But what is really remarkable about Allen's life is that the most interesting, and yes, let's say inspiring, bits were still to come.
Microsoft was not the culmination, but the catalyst.
In a word of hyperbole, Allen was a truly extraordinary man.
A polymath, with a horizon of interests that encompasses human endeavour in its widest, and sometimes wildest, sense.
The billions he earned from Microsoft were used to feed his own intellectual curiosity. And the world often benefited.
If I sound like a breathless fan-boy, then I plead guilty.
But with this mitigation: on the occasions when I have wondered what it would be like to be breathtakingly wealthy, I have invariably come to the conclusion that Paul Allen, above anyone else, played his hand with panache, wisdom and altruism.
Yes, there were the fabulous properties and outsize boats.
But there were also investments in science, the arts, community, sport and exploration.
It was he who funded various searches for the lost wrecks of the Second World War.
Allen's project discovered the resting place of the USS Indianapolis, which delivered the atomic bomb, and also the Japanese warships Musashi, the heaviest armed ship in naval history.
Along with the Titanic, these are some of the greatest, most painstaking, finds on our seabed.
But if wrecks aren't your thing, then try sport.
Allen was a sports fan.
A basketball lover, he bought the Portland Trail Blazers in 1988 and never lost his affection for the team.
In 1996 he bought the Seattle Seahawks American Football team, then threatened with a move to California.
He revitalised it, kept it in Seattle, and saw them reach, and then win, the SuperBowl. He also co-owned the Seattle Sounders football (soccer) team.
He funded groundbreaking science, funding teams to map the brain and making the research freely available.
Cellular research too.
He backed companies that were working on artificial intelligence and passenger space flight.
His curiosity ran from the depth of the ocean to the far side of the atmosphere.
He personally held 43 patents for inventions, and there were hundreds, perhaps thousands, more attached to the companies and institution that he financed.
And, pleasingly for a man who instigated the growth of Silicon Valley, Allen's CV includes court battles with AOL, Apple, eBay, Facebook, Google, Yahoo, YouTube. His brain was the last thing to go.
His philanthropy, of course, will be his great legacy.
He funded campaigning film-making, wildlife conservation and health research.
During the Ebola crisis of 2014, Allen was the world's biggest private donor, bringing together political leaders from a host of counties to co-ordinate a response.
He pledged that at least half his $20bn fortune would be left to charity.
It will do huge good for years, maybe decades, to come.
And so ends a spectacular life.
When you've helped to found Microsoft and become fabulously wealthy by the time you're still a young man, there must have been a temptation to sit back, count the money and live a life of indulgence. Paul Allen didn't do that.
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In fact, he did the reverse – he kept on adding to the sum of knowledge.
And that, I think, is why we will look back upon him with enduring fascination and respect.