King Charles I twice mobilised England in an attempt to enforce religious uniformity in Scotland, and both times he failed. The result was the resurgence of Parliament as partner in the government of the realm. The Bishops' Wars is an essay in military history in a political context, which analyses the institutions of war, its financing, and above all the recruitment of forces. The main purpose of the book is to explain why the King could not and did not reduce Scotland by force. Its significance lies in that it demonstrates how the military failures of 1639 and 1640 were determined by Charles's hand. Moreover, it seeks to show how poor strategic and tactical operations, coupled with the political controversy surrounding the war, plagued the English army. In the final measure, it is concluded that the King must bear responsibility for defeat at the hands of the Scots.