Saint John became a gateway to what is now Canada in the early 1600s, and Fort La Tour, built in 1632, was one of the three main forts of Acadie. In Saint John Fortifications, Roger Sarty and Doug Knight trace the history of the port's defences, from the earliest log palisades to the bunkers, gun emplacements, and communications stations built during World War II. Put to the test during the American Revolutionary War, Saint John has figured as one of Canada's most significant guardians. American independence effectively closed the shipping route between the mouth of the Richelieu River, on the St. Lawrence, and the mouth of the Hudson River, at New York City. Saint John took over some of this traffic, and so the 19th century wars and threatened wars between Canada and the United States resulted in bigger and better fortifications for the city. Each new defence system has incorporated the old, including the installations built as protection from German invasion during the two World Wars. Although the last of the modern installations on Partridge Island was disabled in 1956, many sites still contain substantial reminders of their past strength. Visitors today can trace the evidence of this great commercial port's military past. Saint John Fortifications, 1630-1956 is the first book in the New Brunswick Military Heritage Series published by Goose Lane Editions in collaboration with the New Brunswick Military Heritage Project.