In February 1810, Wellington formed what became the most famous unit in the Peninsular War: the Light Division. Formed around the 43rd and 52nd Light Infantry and the 95th Rifles, the exploits of these three regiments is legendary. Over the next 50 months, the division would fight and win glory in almost every battle and siege of the Peninsular War.

Key to the understanding how the division achieved its fame is an understanding of their excellence and tradition that was established from its founding. It began on the border of Spain and Portugal where it served as a screen between Wellington's Army and the French. For six months while vastly outnumbered, it manned outposts, guarded fords and bridges, and fought numerous skirmishes. When it came time pull back from the border, the division endured a harrowing retreat with a relentless enemy at their heels. It was during this eventful year it developed an esprit-de-corps and a belief in its leaders and itself that was unrivaled in Wellington's Army.

Wellington's Light Division in the Peninsular War uses over 100 primary sources to recount the numerous skirmishes, combats, and battles, as well as the hardships of a year of duty on the front lines. Many of these sources are from British and Portuguese archives and have never been published before. Others are from long-forgotten books published over 150 years ago. It is through the words of the officers and men who served with it that this major, and long-anticipated study of the first critical year of the Light Division is told.