Meticulously researched, "Colonels in Blue" compiles biographical sketches and photographs of the diverse group of men - mostly citizen-soldiers from a wide variety of backgrounds - who attained the rank of colonel in the Union Army and commanded regiments from the states of Pennsylvania, New Jersey, Maryland, Delaware, and the District of Columbia. Profiles contain an overview of each colonel's military career, occupation, dates and places of birth and death, and place of burial. Many rare photos are seen here for the first time. It covers infantry, militia, cavalry, and artillery regiments, including provisional, emergency, and reserve units.