Liberty Fund's edition of The Free Sea is the only translation of Grotius's masterpiece undertaken in his own lifetime, left in manuscript by the English historian, Richard Hakluyt (1552-1616). It also contains William Welwod's critique of Grotius (reprinted for the first time since the seventeenth century) and Grotius's reply to Welwod. These documents provide an indispensable introduction to modern ideas of sovereignty and property as they emerged from the early-modern tradition of natural law. Hugo Grotius (1583-1645) was a lawyer and legal theorist, diplomat and political philosopher, ecumenical activist and theologian. David Armitage is the Lloyd C. Blankfein Professor of History at Harvard University.