First a soldier and only afterward a literary figure, Roger Boyle, earl of Orrery, gave the bulk of his time and energy to the fulfillment of his many military obligations under both Oliver Cromwell and Charles II and pursued his literary interests mainly during periods of leisure forced upon him by illness. Even when he was not engaged in literary pursuits, however, he was a prolific writer of letters, and at the conclusion of his military career he distilled all of his experience as a general into A Treatise of the Art of War(1677), which proposed many innovations in the care and training of common soldiers that are accepted as commonplace today. As a literary figure he is credited with introducing rhymed heroic plays onto the Restoration stage, and his early heroic plays were popular and influential in his own time. He also wrote a heroic romance, Parthenissa...