PULLMAN, Wash.— Popular recreation destinations today, the massive concrete fortifications at the entrance to Puget Sound silently guard an obscure past—one that piqued author David M. Hansen’s curiosity. Not content to simply wonder, the former Washington State preservation officer/historian specializing in military architecture set out to uncover the story behind the structures. Unable to locate a comprehensive, readable history of Admiralty Inlet’s former military sites, he began his own research, completing his original draft in about 1990. After a dispute with a publisher sidelined the printed book, the project lay dormant for more than two decades—until a blizzard left him without power.

With little else to do, he remembered his manuscript. “I put a kerosene lamp on the kitchen table and started to work. By the time power was restored two days later, I had a greatly revised document—the basis of Battle Ready.” Soon he had a publisher as well, Washington State University Press.

Now for the first time, David M. Hansen’s authoritative description and interpretation chronicles the harbor defenses’ origin, construction and use. Carefully selected photographs, many never previously published, supplement the text. Based on extensive research from multiple sources, Battle Ready: The National Coast Defense System and the Fortification of Puget Sound, 1894–1925 untangles the threads of their history and details their significance.

Until the last half of the 19th century, the United States flanked important harbors with big cannon chambered in thick walls of brick and stone—valuable protection in the days of wind-driven warships. But the advent of steel battleships powered by steam engines left key coastal cities vulnerable to attack or invasion. To counter the threat and ensure no warship could pass through Admiralty Inlet, the Army’s Corps of Engineers built an elaborate complex. Their efforts reshaped open land into military terrain and involved the construction of concrete batteries for heavy cannon. Mounted on the “disappearing carriage,” these arsenals were a mechanical novelty and came to symbolize the technical nature of the defenses. Searchlights concealed in concrete shelters enabled servicemen to fire weapons at night. To assist with aim, troops used powerful telescopes housed in specially designed structures. For a while, it all worked, but in an era characterized by rapid technological change, innovations were soon obsolete. By World War I, newer warships were capable of penetrating Puget Sound’s “Triangle of Fire,” and armed forces gradually abandoned permanent fortifications in favor of mobile artillery. The decline culminated in the 1950s, when the military passed the forts to Washington State. The sites remain enigmatic as well as visually impressive—kind of a Northwest Machu Picchu.