During the 18th century, visitors would come and attend the British Parliament sessions in order to understand how a representative assembly could technically function, because politics is not only about ideas, but also a lot about practices and techniques. A great deal has been written on the circulation of political ideas during the 19th century, and on the part played by exiles, refugees and military volunteers in this intellectual mobility. However, less is known of what constitutes, in the end, politics: not only ideas, but practices, the material implementation of politics. How does one debate, vote, or demonstrate? What is political representation? How does one “start” a political party, and run it? All the political engineering, of the 19th century, the period of the birth of modern politics, has been the result of an intense circulation of exiles, which, along with bringing in new ideas, borrowed new ways of “making politics”. This is what this book contemplates through a wide range of examples showing how exile turned out to be, during the century of the revolutions, the laboratory of a new political grammar and of political practices resulting in the cross-fertilization between host countries and exiled communities.