Book excerpt: The occupation of San Juan Island by the Royal Marines between 1860 and 1872 marked the last time "redcoats" would be stationed in lands south of the 49th parallel. Following the nearly disastrous "Pig War" crisis, their primary mission with their U.S. Army counterparts was keeping the peace on an island considered ripe for the taking by Britons and Americans alike. Drawing on historical, archaeological and photographic research, Outpost of Empire offers an intriguing glimpse of a frontier garrison in the Victorian age. Mike Vouri is the San Juan National Park historian and author of The Pig War.