Alexander Gordon was no ordinary soldier. In the Coruna campaign of 1808-9 he served as aide-de-camp to his uncle, Sir David Baird; then, in 1809, he joined Wellington's staff shortly before the battle of Talavera and remained at Wellington's side throughout the Peninsular War and in the Waterloo campaign. Both Baird and Wellington trusted him implicitly and he was perfectly placed to see how their plans developed. His long, confidential letters home to his brother, Lord Aberdeen, provide a unique insight into the British campaigns in the Peninsula. Written weekly or, at particularly interesting times, as a daily journal the letters record every twist and turn, every raised hope and false alarm of the campaigns and often explain the thinking which lay behind Wellington's operations more fully than in Wellington's own despatches. The letters represent an important source on the Peninsular War.