Peter Baldwin is interested especially in the historical development of the modern state––a broad field that has led him in many different directions. Two aspects of his work unify it. First, he has attempted to understand contemporary issues in a long historical perspective, whether that be the class coalitions that cemented the modern welfare state, the 19C public health strategies that provided the template by which the AIDS epidemic was fought a century later, or the battles over intellectual property stretching back three centuries that inform, indeed determine, our current battles over copyright, downloading and internet piracy. Second, he has studied the development of the state trans-nationally, using detailed and often archival sources in half a dozen languages to marry a broad comparative approach to rigorous empiricism. His books have dealt above all with France, Germany, Britain, Sweden, Denmark and the United States. He has published works on the comparative history of the welfare state, on social policy more broadly and on public health. Other interests have included Nazi Germany and historiography. His latest book is a trans-national political history of copyright from 1710 to the present. He is working on a global history of the state.