This book is a sequel of sorts. Sixteen years ago, its author published a work entitled Republics Ancient and Modern: Classical Republicanism and the American Revolution. Although it was some twelve hundred pages in length, inevitably, it gave some figures short shrift, and others it neglected entirely. Niccolò Machiavelli was discussed and his importance was underlined, but his thinking was not treated in depth. John Milton and Marchamont Nedham were not mentioned at all. Thomas Hobbes was accorded a chapter, but little was said about the evolution of his thought; and, while James Harrington's significance was emphasized, the foundations of his thinking were not discussed at length.

What follows is an attempt to redress the balance – to do justice to Milton and Nedham, to explore in greater depth the thinking of Machiavelli and Hobbes, and to provide a setting within which to understand Harrington. Its purview is the political opening that took place in the period that began on 30 January 1649 – when the execution of a recalcitrant English king occasioned an abortive experiment in the construction of a republic in Britain – and that ended on 1 May 1660, when a Parliament more or less freely elected voted to recall to the throne that king's eldest son. Its subject is the republican speculation, of a sort hitherto unprecedented, to which this brief, abortive experiment gave rise.