From the back cover:

This highly detailed study provides a clear account of how the British Army was organised, who commanded it, and how it functioned in the field during the Peninsular War. Focusing principally on infantry, cavalry and artillery, including foreign units in British pay, it provides a detailed and comprehensive order of battle. Doctrine, training, tactics and equipment are discussed in depth, and medical services and engineers are also covered. Concise biographical details of key commanders, over 60 unit tree diagrams, organisational tables, plus numerous illustrations make this an essential reference work for students of this period.