The interplay of roles of the Marquess of Argyll, as clan chief, Scottish magnate and influential British statesman, make him a worthy counterpoint to Cromwell. This book reviews Argyll's formative influence in shaping British frontier policy during the period 1607–38 and his radical, financially creative and highly partial leadership of the Covenanting Movement in Scotland, 1638–45, when Covenanters rather than Royalists or Parliamentarians directed the political agenda in Britain. It examines his role as reluctant but calculated revolutionary in pursuing confessional confederation throughout the British Isles, and in restoring Scotland's international relations particularly with France. His ambivalent role as a military leader is contrasted with that of his genius as a political operator, 1646–51. Reappraising his trial and execution as a scapegoat for reputedly collaborating with Oliver Cromwell and the regicides who executed Charles I in the 1650s, it rehabilitates Argyll's reputation as a tarnished Covenanting hero rather than an unalloyed Royalist villain. The book is firmly grounded in public and private archival sources in the UK, the USA and Scandinavia, and draws especially on privileged access to archives in Inveraray Castle, Argyllshire. It should appeal to those interested in clanship, civil war and British state formation.