The five British and Canadian generals depicted in Corps Commanders were a surprisingly eclectic lot – one a consummate actor, one a quiet gentleman, one a master bureaucrat, one a brainy sort with little will, and the last a brain with will to spare. And yet they all fit readily into British Commonwealth armies and fought their corps in similar fashion. All three Canadians controlled British formations and served under British army commanders, and the two Britons worked for and led Canadians as well. Such inter-army adjustments were relatively simple because they all spoke the same “language” – a common method for solving military problems and communicating solutions. Like all senior commanders in the British Commonwealth, they learned the language of the staff colleges at Camberley and Quetta, and so did the staff officers that served them. This allowed a gunner from Montreal to understand a guardsman from London with ease – no small advantage when coordinating coalition battles involving tens of thousands of troops. In probing how these corps commanders fought, Douglas E. Delaney has produced an invaluable study for anyone interested in coalition warfare, interoperability, or how men managed large formations in war.