The United States had few military vehicles in its arsenal when in April 1917 it declared war and joined Britain, France and Russia in the horrific struggle that was the Great War. But if America’s supply of tanks and troop carriers was meager, its civilian auto fleet was substantial: More than 1.8 million cars were manufactured in the country in 1917.

As a result, some of the first vehicles to go “over there” were passenger cars, and among them were the personal automobiles of volunteers. Most never returned.

One that did was a 1918 Cadillac Type 57 touring car bought new by John H. Denison, a Presbyterian minister who served with the Y.M.C.A. in a troop support role. A survivor that is complete and largely untouched, this Cadillac was the 257th passenger vehicle to arrive in Europe among some 20,000 that would eventually serve.

Now owned by Marc Lassen of Gardiner, Wash., it is scheduled for display at the Concours d’Élégance of America at St. John’s in Plymouth Mich., on July 27. There, amid all the shiny paint and gleaming chrome, the Cadillac, which was recently added to the National Historic Vehicle Register, may well be overlooked.