Between the start of the 17th century and the end of the 18th, an Atlantic world took shape. The regions bordering the ocean, in Europe, the Americas and Africa, were all involved in what became, in many respects, a single economic and cultural entity. Commodities and people, like beliefs and ideas, moved constantly to and fro across the waters. They included people treated as commodities: African slaves, transported convicts, indentured labourers. As historians have increasingly recognised, it makes more sense to think of this era, and these people's lives, in terms of the Atlantic's seaways and its shores than by way of distinct national or state- centred histories, the English, the American, the Irish or Jamaican.
Yet this was also a world that aggressive, expansionist states - above all the British - were trying to control, and one where modern mercantile capitalism was flexing its adolescent muscles. It was those forces of state power and the market economy, including the market in human beings, which triumphed in the long run. But they were resisted, in a range of ways and by a remarkable variety of people: rebellious African slaves, disgruntled labourers and peasants, dispossessed Native Americans, pirates, proto-anarchists and religious visionaries, mutinous sailors and soldiers, and a few dissident poets and clerics. Some struggled simply to escape their own harsh circumstances, some to assert the values of a "moral economy" against the iron-hard laws of market and state, and some in pursuit of a utopian future of perfect freedom and equality - which one of them, Jamaican-born Robert Wedderburn, called the "Jubilee". Remarkably often, their improvised coalitions of protest and rebellion crossed racial as well as national lines.
This strange array of insurgents was what their enemies often called "the many-headed hydra". In the end, all their efforts failed, and most rapidly disappeared both from popular memory and from the historical record. Yet, as Peter Linebaugh and Marcus Rediker urge in this passionate effort to resurrect their lost stories, they helped inspire the American and French revolutions, as well as the art of Blake and Shelley, while some of their utopian spirit survives in a myriad protest movements today.
The Many-Headed Hydra is not just a book about early-modern history, then, but an intensely politically engaged work. Both Linebaugh and Rediker are middle-aged Americans, both distinguished scholars, but their book could quite easily be the product of two student revolutionaries, fired with the spirit of May 1968. The romantic leftist historian's celebration of resistance, classically enshrined in works such as Christopher Hill's The World Turned Upside Down (1972) and E P Thompson's Making of the English Working Class (1963), finds here a glorious late flowering.
In the Sixties, it was possible for Marxist historians such as Hill and Thompson to believe that the 17th- and 18th-century rebels and visionaries they chronicled were not just historical curiosities, but bearers of a revolutionary possibility that could still be realised in the future. Today, such hopes have almost vanished; and Linebaugh and Rediker are writing in a political climate where their kind of romantic, even sentimental, leftism seems isolated and anachronistic. It cannot any longer easily be argued that their heroes represent the future, as opposed to a long-lost past. Shorn of such dreams, as the embers of 1968 grow ever colder, theirs becomes an act of faith, or a simple cheering on of past, doomed registers, applauding the mere fact of resistance as an end in itself.
The passions and the sympathies that are the book's glory are also, then, the source of its flaws. Linebaugh and Rediker's attempt to depict 18th-century pirates as politically admirable rebels is perhaps the least convincing aspect, an extreme instance of the recurrent tendency among intellectuals to find counter-cultural heroes lurking within every thug and gangster. (Think of the Ned Kelly legend, which Peter Carey brilliantly reworked in his recent novel, or, for that matter, the cult of the rap star Eminem.)
True, pirate crews often practised a rough-and-ready egalitarianism. And the existence of a few women pirates and black bandits, as well as scattered hints of pirate homosexuality, have set some enthusiasts deep-sea-dreaming about the buccaneering world as a lost paradise of feminism, racial equality and gay rights. But fantasies ignore the evidence of the pirates' extreme brutality, sexual exploitation and racism - some pirate crews had African members, but others were enthusiastic slave-dealers.
The Many-Headed Hydra arouses intensely mixed reactions. On one level, it is a piece of soi-disant revolutionary romanticism, but on the other, more important level, it is an impressive exercise in historical reconstruction and imagination. For all its faults, there won't be many more impressive, or more enjoyable, history books published this year.
Stephen Howe's most recent book is Ireland and Empire (OUP, £25)