Samuel H. Walker was an apprentice carpenter in Washington, D.C., when the second Seminole War broke out in 1838. He enlisted in a Washington militia unit and went to Florida. Upon the expiration of the unit's service, he was employed in the construction of the railroad from Mobile to Pensacola. Upon the completion of his labors, he removed to Texas where he joined the ill-fated Mier Expedition in 1842, being subsequently imprisoned by the Mexican authorities for two years, during which time he developed an intense hatred for his captors. Upon his release, he returned to Texas and joined the Texas Rangers. When war broke between the United States and Mexico in 1846, Walker joined the 1st Regiment of Texas Mounted Rifle Volunteers before, at the request of General Zachary Taylor, forming his own company of scouts. He subsequently returned to the Texas Mounted Rifles and was elected lieutenant colonel of the regiment.

His term of service with Texas finished, he was commissioned as a captain in the U.S. Mounted Rifles and journeyed north to recruit his company. During this time, he met Samuel Colt. His discussions with Colt resulted in the Walker Colt pistol. His company filled, Walker returned to Mexico and the scene of battle. There, in 1847 Walker led a furious charge against the remnants of the Mexican dictator Santa Ana's army in which he was mortally wounded by a Mexican sniper.

Based upon archival materials including Walker's own letters--he was a well-educated man and wrote extremely descriptive accounts of his experiences--this is the first in-depth biography of Walker.