Peadar O'Donnell (1893-1986) was a major radical figure in the history of twentieth century Ireland. A socialist, Republican and a writer who saw his pen as a weapon in the revolutionary process, he moved from his role as a trade union organiser to the senior ranks of the IRA during the War of Independence and the Irish Civil War. A key figure in the Republican-Communist nexus of the late twenties and early thirties, O'Donnell was the instigator of the mass campaign against the payment of land annuities to Britain, an issue that helped Fianna Fail to power in 1932 and sparked off the Economic War. As editor of the legendary Bell magazine in the late forties and early fifties he encouraged writers to engage with social and political realities, while he continued to agitate and campaign on behalf of emigrants, the small farm countryside and other marginalised sections of Irish society. He grew into his role as 'the grand old man of the left', inspiring successive generations of activists to take up the struggle and lending his symbolic weight to many progressive political causes. In this new biography, Donal Ó Drisceoil critically examines Peader O'Donnell's political and cultural role and influence, standing on the shoulders of a unique participant in public life to gain new perspectives on the dynamics of Irish politics, culture and society in the twentieth century. Donal Ó Drisceoil lectures in History in the Department of History, University College, Cork.