Privacy advocate Caspar Bowden has died, according to German site Netzpolitik.org. Bowden was well known in the privacy community as an outspoken activist concerned about mass government surveillance, even before the Snowden revelations broke. 

Bowden was well known to the IAPP community, having worked as Microsoft’s chief privacy advisor from 2002 to 2011. In that role, he spoke at the very first IAPP Privacy Academy in 2003. His departure from the company was tied in with his concerns about U.S. surveillance policies and the National Security Agency's relationships with private business.  

Before Microsoft, he worked as the director of the Foundation for Information Policy Research; Internet Consultant for Qualia and financial strategist for Goldman Sachs. He attended Cambridge University.

In early 2013, before the Snowden revelations would hit that summer, Bowden co-authored a report warning that the U.S. Foreign Intelligence and Surveillance Amendments Act could have grave consequences for non-U.S. citizens, citing risks to "EU-data sovereignty" given that it applies to cloud computing and gives U.S. agencies the power to surveill non-Americans, as Slate reported. 

Fellow privacy advocate Justin Brookman told The Privacy Advisor, “Caspar was a dedicated and brilliant advocate, and a deeply caring person. He knew as much about intelligence law as anyone I've ever met.  Occasionally he forgot that not everyone knew as much as he did when explaining the NSA's excesses, but he would be happy to patiently explain the minutiae of the FISA Amendments Act to anyone who was interested. He was one of the first to fully recognize just how the rise in cloud processing empowers state surveillance. He spent his life trying to protect individual liberty, and I will miss him."

Bowden had a strong presence on Twitter, with more than 5,000 followers. Most of the posts on his feed focused on the perils of government surveillance, especially in the U.S. and UK, and bulk data collection. In 2013, Bowden said at a conference in Switzerland that he hadn't traveled with a cell phone for two years prior, and said law under which the National Security Agency was collecting bulk data meant, "If you're not American, there's no protection," as reported by The Guardian. 

The Twittersphere has been blowing up today with reactions to Bowden’s death. 

From Tor and other major privacy and civil liberties organizations:

Caspar Bowden, a passionate advocate for information privacy, and indeed human rights, has passed away. pic.twitter.com/cQUU6Fbfi9
— torproject (@torproject) July 9, 2015

The death of @CasparBowden is a loss to us all. He foresaw Prism and Tempora. He took on RIP Bill nearly single-handedly. We need him now.
— PrivacyInternational (@privacyint) July 9, 2015

Truly saddened to hear of the passing of Internet activist @CasparBowden, who's positive impact on world will be felt for many years to come
— IP Justice (@ipjustice) July 9, 2015

To academics:

Thinking fondly of UK visit when Caspar Bowden hosted an amazing group for a privacy salon. A brilliant and kind man who will be missed.
— Paul Ohm (@paulohm) July 9, 2015

The passing of @CasparBowden is a sad day for #privacy. Committed, knowledgeable advocate for the cause. RIP friend pic.twitter.com/x3lHVdtpHX
— Omer Tene (@omertene) July 9, 2015

As well as privacy pros and advocates:

Privacy lost one of its loudest voices. @CasparBowden was a champion for human rights and will be missed! https://t.co/meNrvFYZMy
— Andy Roth (@ndyroth) July 9, 2015

So sad to learn we've lost @CasparBowden, one of the OG privacy advocates. Always admired him. Deeply knowledgable, principled, unwavering.
— Marcia Hofmann (@marciahofmann) July 9, 2015

Sad to hear the privacy community has lost one of our own, @CasparBowden http://t.co/iyRSJUQVvQ
— Julian Sanchez (@normative) July 9, 2015

Dearest privacy fighter @CasparBowden passed away - Remember his message "equal privacy protection for everyone regardless of frontiers!"
— Katitza Rodriguez (@txitua) July 9, 2015

Reporters and bloggers chimed in:

I am deeply, deeply saddened to hear that @CasparBowden has passed https://t.co/bxUoHiayUh
— David Meyer (@superglaze) July 9, 2015

.@CasparBowden made many valuable contributions to the privacy debate. This was one of the most important: http://t.co/KqU8dArkx2 RIP
— David Meyer (@superglaze) July 9, 2015

Oh no. This is terrible news. https://t.co/7aGzIoV0nV
— Mike Masnick (@mmasnick) July 9, 2015

Absolutely shocked that @CasparBowden has passed. Was a huge admirer, was flattering to communicate with him. Deserves all of our tributes.
— Alexander J. Martin (@lexanderjmartin) July 9, 2015

Very sad to hear we've list Caspar - a fierce defender of our digital rights. https://t.co/4Uchogw7Lx
— Simon Phipps (@webmink) July 9, 2015

Not to mention some of the world's top security experts and digital activists:

Earth lost @CasparBowden today. He was a voice of moral and legal leadership in the privacy community. He will be deeply and sorely missed.
— Jacob Appelbaum (@ioerror) July 9, 2015

In the hospital @CasparBowden asked that we work to ensure equal protection regardless of nationality. Privacy is a universal human right.
— Jacob Appelbaum (@ioerror) July 9, 2015

.@CasparBowden on the "nothing to hide" argument: http://t.co/167pB9i3rC pic.twitter.com/DwbgQ5vh8g
— Maria Xynou (@maria_xyn) July 9, 2015

.@lmbrownlee1 here's one of Caspar's more recent interviews, including the problem w/ the “nothing to hide” argument: http://t.co/QEpgKwkgOp— Kenn White (@kennwhite) July 9, 2015

> @MalJayaram My visit to the @CasparBowden residence in France, skyrockets, booze & cryptopolitics: https://t.co/ns7Es44a3f— Alec Muffett (@AlecMuffett) July 9, 2015

A tragedy to hear the passing away of @CasparBowden. A true hero to our cause. An immutable voice of moral courage. https://t.co/Oh7e8ke4KI— TheCthulhu (@CthulhuSec) July 9, 2015

RIP Caspar Bowden :/ A man of great value, who understood the techno-political architrcture of surveillance before most of everyone else. <3— Jérémie Zimmermann (@jerezim) July 9, 2015