After failing to strike any decisive blow against the Royalists, Robert Devereux, 3rd Earl of Essex, who commanded the first Parliamentarian army against King Charles I, never achieved military distinction. This account of Essex’s campaigns, which includes analysis of the battles of Edgehill, Lostwithiel and Newbury, reappraises the man and his reputation in the light of his military accomplishments, his strategic influence over the battles, and his loyalty to his men.