Lieutenants and Light provides an accurate, detailed historical study of the U.S. Army’s use of the heliograph as a tactical means of communication and command and control in the desert environment of Arizona and New Mexico in the late nineteenth century.The heliograph network in the Southwest, which began development in 1882, used mirror-based signaling devices to facilitate communication across remote outposts, forts, and detachments. Heliographs enabled...