A global history of free speech, from the ancient world to today. Hailed as the "first freedom," free speech is the bedrock of democracy. But it is a challenging principle, subject to erosion in times of upheaval. Today, in democracies and authoritarian states around the world, it is on the retreat. In Free Speech, Jacob Mchangama traces the riveting legal, political, and cultural history of this idea. Through captivating stories of free speech's many defenders - from the ancient Athenian orator Demosthenes and the ninth-century freethinker al-Razi, to Mary Wollstonecraft, Mahatma Gandhi, Nelson Mandela and modern-day digital activists - Mchangama demonstrates how the free exchange of ideas underlies all intellectual achievement and has enabled the advancement of both freedom and equality worldwide. Yet the desire to restrict speech is also a constant, and he explores how even its champions can be led down this path when the rise of new and contrarian voices challenge power and privilege of all kinds. Meticulously researched, deeply humane and provocative, Free Speech challenges us all to recognise how much we have gained from this principle - and how much we stand to lose without it.