Published in 1936, the Instruction on the Tactical Employment of Large Units was referred to by French army officers as the "Bible" of their military doctrine. Intended for the commanders of divisional units and higher, it was the central document on which the French Army's tactical regulations and instructions were based at the start of the Second World War. This English translation of the Instruction is an important resource for historians and students of military history to more fully understand the military operations during the opening days of World War II. This is the first in a planned series of translations of French and Italian World War 2 military manuals covering the tactical doctrines of those two countries.