The beloved Mr. Sulu from the original Star Trek, George Takei is an activist for human rights (and a master of Facebook memes).

From his home base in Bulgaria, Ivan Krastev thinks about democracy -- and how to reframe it.

Robb Willer's political research has investigated various topics, including economic inequality, racial prejudice, masculine overcompensation and Americans' views of climate change.

When her hashtag #IfAfricaWasABar went viral, Botswana writer Siyanda Mohutsiwa triggered a lighthearted but electrifying discussion of some serious African issues.

Sayu Bhojwani recruits and supports first and second generation Americans to run for public office.

Yanis Varoufakis thinks we need a radically new way of thinking about the economy, finance and capitalism.

Heather Brooke campaigns for freedom of information, requesting one secret document at a time.

Wael Ghonim believes that the Internet can be the most powerful platform for connecting humanity, if we can bring civility and thoughtful conversations back to it.

As CEO of Citizen University, Eric Liu is working to spark a civic revival in the US and beyond.

With books and strategies, David Rothkopf helps people navigate the perils and opportunities of our contemporary geopolitical landscape.

Using software to inspire public debate and enable voter engagement, Pia Mancini hopes to upgrade modern democracy in Argentina and beyond.

As a cofounder of Upworthy, and the author of "The Filter Bubble," Eli Pariser leverages technology to help build better and more democratic societies.

Farida Nabourema is a key voice in Togo’s pro-democracy movement.

Tshering Tobgay is the president of the People's Democratic Party in Bhutan.

Thomas Piketty is an economist and professor at the Paris School of Economics. His 2014 book, "Capital in the Twenty-first Century," caused a sensation upon publication.

Erica Stone works at the intersection of writing, teaching, and community organizing.

Michael Patrick Lynch examines truth, democracy, public discourse and the ethics of technology in the age of big data.

Shad Begum is a women's rights activist working for the economic and political empowerment of women and youth in Khyber Pakhtunkhwa, a province in the northwest of Pakistan.

Brett Hennig co-founded and directs the Sortition Foundation, which campaigns to institute the use of stratified, random selection (also called sortition) in government.

Garry Kasparov is esteemed by many as the greatest chess player of all time. Now he’s engaged in a game with far higher stakes: the preservation of freedom and democracy.

Danielle Allen is an expert on the intersection of ethics and democracy.

Sviatlana Tsikhanouskaya is the leader of democratic Belarus.

Bhu Srinivasan writes about economics, history and statecraft.

Baratunde Thurston is an Emmy-nominated writer, activist and comedian who addresses serious issues with depth, wit and calls to action. He believes the stories we tell help shape the world in which we live. Also, he's from the future.

Amber McReynolds's vision is to create election systems that put voters first and improve the voting experience for all.

After years spent as a CIA analyst, diplomat and national security advisor at the White House, Yaël Eisenstat began to view the breakdown of civil discourse as the biggest threat to US democracy.

As President of Sierra Leone, Julius Maada Bio seeks to find ways to make progress happen -- not to dwell on the obstacles that impede it.

As a leader of the Participatory Budgeting Project, Shari Davis enriches democracy by returning the reins of government budgeting to the people.

Reuben Jonathan Miller is a sociologist, criminologist and social worker whose work centers on race, democracy and the social life of the city.

Nick Hanauer is one of the world’s most provocative thinkers about our society’s growing inequality and the dire consequences it creates for our democracies.