Since the mid-19th century the art and practices of war, spurred on by the revolution in technology, have changed fundamentally and at increasing speed. It has therefore become supremely difficult to keep abreast of current events and to remain aware of the implications of past developments. This encyclopaedia provides a compact guide to the events and developments of the past 150 years, covering the principal wars, campaigns, battles and personalities of the period, together with descriptions of evolving strategy, tactics and intelligence handling. It also provides background knowledge on logistics, weapons and technology, military philosophy and the laws of war.