Wikipedia defines activism as 'efforts to promote, impede, or direct social, political, economic, or environmental reform or stasis with the desire to make improvements in society.' It also says that 'forms of activism range from writing letters to newspapers or to politicians, political campaigning, economic activism such as boycotts or preferentially patronizing businesses, rallies, street marches, strikes, sit-ins, and hunger strikes.'
In short, activists want to change the world for better.


Social

Occupy by Noam Chomsky

No Place to Hide: Edward Snowden by Glenn Greenwald

Dirty Wars: The World Is a Battlefield by Jeremy Scahill

This Changes Everything: Capitalism vs. The Climate by Naomi Klein

The Divide: American Injustice in the Age of the Wealth Gap by Matt Taibbi

Direct Action: An Ethnography by David Graeber

Race Matters by Cornel West

What Gandhi Says: About Nonviolence by Norman G. Finkelstein

What Then Must We Do? by Gar Alperovitz

No Turning Back: The History of Feminism and the Future of Women by Estelle Freedman

Rebel Cities: From the Right to the City to the Urban Revolution by David Harvey

The Syria Dilemma by Danny Postel

Silent Spring by Rachel Carson

Hiroshima by John Hersey

Mountains Beyond Mountains: One doctor’s quest to heal the world by Tracy Kidder

Ill Fares the Land by Tony Judt

PostCapitalism: A Guide to Our Future by Paul Mason

War Is a Force that Gives Us Meaning by Chris Hedges

America Right or Wrong: An Anatomy of American Nationalism by Anatol Lieven

Unstoppable: The Emerging Left-Right Alliance to Dismantle the Corporate State by Ralph Nader

The Boy Who Could Change the World by Aaron Swartz

To Save Everything by Evgeny Morozov

Beyond the Green Zone by Dahr Jamail

What’s Wrong With a Free Lunch? by Philippe van Parijs

Masscult and Midcult: Essays Against the American Grain by Dwight Macdonald

Why Nuclear Disarmament Matters by Hans Blix

Unpeople: Britain’s Secret Human Rights Abuses by Mark Curtis

The Spirit Level: Why Greater Equality Makes Societies Stronger by Richard G. Wilkinson

Economics: The User’s Guide by Ha-Joon Chang

The Age of Extremes: 1914–1991 by Eric Hobsbawm

Culture and Imperialism by Edward W. Said

The End of Nature by Bill McKibben

The Precariat: The New Dangerous Class by Guy Standing

Lawless World by Philippe Sands

How Much is Enough?: Money and the Good Life by Robert Skidelsky

How Corrupt is Britain? by David Whyte

The People’s Spring: The Future of the Arab Revolution by Samir Amin

The ABCs of Political Economy: A Modern Approach by Robin Hahnel

Whoops!: Why everyone owes everyone and no one can pay by John Lanchester

Why Not Socialism? by G. A. Cohen

A People’s History of the United States by Howard Zinn

In Praise of Idleness by Bertrand Russell

Feminism is for Everybody by bell hooks

PR! — A Social History of Spin by Stuart Ewen

Stonewall by Martin Duberman

Perpetual War for Perpetual Peace by Gore Vidal

The Keynes Solution: The Path to Global Economic Prosperity by Paul Davidson

Hell and High Water: Climate Change by Alastair McIntosh

Globalisation Development and Social Justice by Ann El Khoury

Making Peace with the Earth by Vandana Shiva

Unequal Democracy: The Political Economy of the New Gilded Age by Larry M. Bartels

How America Gets Away with Murder by Michael Mandel

Unholy Wars: Afghanistan by John Cooley

How Rich Countries Got Rich and Why Poor Countries Stay Poor by Erik S. Reinert

The Cultural Cold War: The CIA and the World of Arts and Letters by Frances Stonor Saunders

Israel/Palestine: How to End the War of 1948 by Tanya Reinhart

Contours of Descent: U.S. Economic Fractures and the Landscape of Global Austerity by Robert Pollin

Crucible of Resistance: Greece by Euclid Tsakalotos

The Autobiography of Malcolm X by Malcolm X

The Sorrows of Empire: Militarism by Chalmers Johnson

Democracy Incorporated: Managed Democracy and the Specter of Inverted Totalitarianism by Sheldon S. Wolin

Rich Media by Robert W. McChesney

No Good Men Among the Living: America by Anand Gopal

Weapons of the Weak: Everyday Forms of Peasant Resistance by James Scott

Austerity: The History of a Dangerous Idea by Mark Blyth

Waste: Uncovering the Global Food Scandal by Tristram Stuart

The Corporation: The Pathological Pursuit of Profit and Power by Joel Bakan

The Killing Fields of Inequality by Goran Therborn

Confronting the Bomb: A Short History of the World Nuclear Disarmament Movement by Lawrence Wittner

Spoils of War: The Human Cost of America’s Arms Trade by John Tirman

Famine Crimes: Politics & the Disaster Relief Industry in Africa by Alex de Waal

Inevitable Revolutions: The United States in Central America by Walter LaFeber

Empire As A Way of Life by William Appleman Williams

The Record of the Paper: How the New York Times Misreports US Foreign Policy by Richard Falk

Walking with the Comrades by Arundhati Roy

Anders Breivik and the Rise of Islamophobia by Sindre Bangstad

The Triumph of the Political Class by Peter Oborne

Eichmann in Jerusalem by Hannah Arendt

13 Bankers: The Wall Street Takeover and the Next Financial Meltdown by Simon Johnson

Fear: The History of a Political Idea by Corey Robin

Open Veins of Latin America: Five Centuries of the Pillage of a Continent by Eduardo Galeano

Who Are We — And Should It Matter in the 21st Century? by Gary Younge

World Hunger: Twelve Myths by Frances Moore Lappe

Communitas: Means of Livelihood and Ways of Life by Paul Goodman

Treasure Islands: Uncovering the Damage of Offshore Banking and Tax Havens by Nicholas Shaxson

The Rule of Law by Tom Bingham

Republic by Lawrence Lessig

Stuffed and Starved: The Hidden Battle for the World Food System by Raj Patel

Killing Hope by William Blum

Amusing Ourselves to Death by Neil Postman

Drinking the Sea at Gaza: Days and Nights in a Land Under Siege by Amira Hass

In Praise of Barbarians: Essays against Empire by Mike Davis

Collapse: How Societies Choose to Fail or Succeed by Jared Diamond

Nickel and Dimed: On (Not) Getting By in America by Barbara Ehrenreich

Hack Attack: The Inside Story of How the Truth Caught Up with Rupert Murdoch by Nick Davies

Activists in City Hall by Pierre Clavel

Disciplined Minds by Jeff Schmidt

Death Without Weeping: The Violence of Everyday Life in Brazil by Nancy Scheper-Hughes

Walden and Civil Disobedience by Henry David Thoreau