Walter P. Lane emigrated from Ireland as a young boy, fought in three wars, sailed the Texas coast with a privateer, and traveled to California and Arizona in search of gold. What drove this man, who in many ways typifies the adventurers who contributed to the westward expansion in the United States during the early nineteenth century? Through his mining of personal papers, memoirs, contemporary sources, and archived collections, Jimmy L. Bryan Jr. has produced a comprehensive portrait of the man who charged across the field at San Jacinto, aided in the removal of Indians and Tejano settlers from the East Texas Redlands, stormed Monterrey with the Texas Rangers during the U.S.-Mexican War, commanded a brigade of Confederate soldiers during the Civil War, supported the return to white rule during the turbulent Reconstruction era, and served the State of Texas in various public capacities. Bryan shows how the adventurism of Lane and his comrades provided both ethos and impetus for the westward migration. More Zeal than Discretion will appeal to historians and readers interested in Texas and the West, the Civil War, and the culture of American manhood.