Professor of Military History at the University of Leeds, John Childs specialises in military history from the 16th to the 20th centuries. He is a Trustee of the Royal Armouries, an advisor and panellist on battlefields and fortification to English Heritage, and associate editor of the New Dictionary Of National Biography.

During the 17th century, technological evolutions in fortifications and arms meant that wars grew longer, armies larger, and military formations more disciplined. Yet, militias remained primarily mercenary; although armaments developed from the pike to the socket bayonet and uniforms began to appear, professionalism remained low. From the multifaceted conflicts of the Thirty Years' War to the campaigns of Louis XIV, a richly detailed picture emerges of military life and structure in the 1600s--its conflicts and conduct, the rise of a standing army, the difficulties posed by reliance on paid soldiers, the changing weaponry, the politics overseeing it all, and the relentless world shift from ancient to modern.