This book is not only intended for a general readership, but also for military researchers and historians who often find that they get lost in the huge and arcane raft of terminology employed by the army during the conflict. It is an essential guide resting on the elbow of every serious historian as they undertake research using primary and secondary sources, and of every reader exploring secondary sources about the war. No such reference book as this exists. The author is an experienced military historian with a background in British Army history, and yet even he often found himself stumped when reading War Diaries, National Archive documents, and other primary sources. The text consists of the following main sections: - Abbreviations and acronyms - Units, regiments and corps - A full glossary of military concepts and terminology - British army slang - Operational names As well as general military terms, a great deal of effort has gone into looking at the often deeply technical and even arcane terminology used not only by the commanders and their staff and the combat units, but also by the multitude of supporting organisations, including artillery, engineering, supply and transport, and medical. What's a BM? It's a Band Master, a Beach Master, a Brigade Major and a Bending Moment in bridging!