Earl J. Hess 
Trench Warfare under Grant and Lee [PDF ebook] 
Field Fortifications in the Overland Campaign

Earl J.Hess’s study of armies and fortifications turns to the 1864 Overland Campaign to cover battles from the Wilderness to Cold Harbor. Drawing on meticulous research in primary sources and careful examination of battlefields at the Wilderness, Spotsylvania, North Anna, Bermuda Hundred, and Cold Harbor, , Hess analyzes Union and Confederate movements and tactics and the new way Grant and Lee employed entrenchments in an evolving style of battle. Hess argues that Grant’s relentless and pressing attacks kept the armies always within striking distance, compelling soldiers to dig in for protection.