Following a chronological format the book confronts head-on the intriguing puzzle of why and how the Cromwell of 1640, an obscure middle-aged man, lacking in political and military experience, rapidly acquired a reputation as a soldier of genius and within 13 years rose to become ruler of England, Wales, Scotland and Ireland. Running through the book is an attempt to reveal what caused Cromwell (at times) to act with agonizing indecisiveness and (at other times) drove him to take awesome risks, apparently disregarding his own political future and personal safety. Cromwell's motives and actions are clouded by much that has been written about him since his own day that is either bitterly hostile or excessively adulatory. This book attempts to by-pass such distorting comments by analyzing Cromwell's words and actions in their proper historical context. One surprising result is the revelation of a consistent thread running through a career that sometimes seems to be inconsistent and contradictory. Cromwell's political and religious aims - what he called "the godly reformation" - were ones he developed during and immediately after the Civil War in debates on military campaigns with fellow soldiers and with political allies at Westminster, and these remained the bedrock of his ambitions until the very end of his life.