The so-called 'Dreadnought Revolution' was a modernization plan, instigated by First Sea Lord Jacky Fisher, which replaced all frontline ships of the Royal Navy with 'all big gun' designs driven by faster, more efficient steam turbine engines. This review of the battlecruiser class vessels of this period includes original plans and drawings and an analysis of the design, construction, armament and machinery of the 15 ships built, including Invincible and Indefatigable.