California at War is a well-researched and well-written study that offers something for historians in all fields. World War I propelled California into the modern age and the impact of the conflict affected its citizens from all walks of life. Dividing her book into three lengthy sections, University of Maryland history professor Diane T. North covers the men and women who served overseas, the impact of war on the home front, and lastly, the encroachment on civil liberties, especially through interference by the American Protective League (APL). Californians served overseas with the Allies well before the U.S. joined the fray in 1917. In a chapter titled “The Great Adventure,” North highlights some of these veterans, including in the American Field Service, the French Foreign Legion and the Lafayette Escadrille. As expected, it is the state’s doughboys fighting with the American Expeditionary Forces (AEF) who receive the most attention. California was well-represented in all of the 1918 Western Front battles, as well as operations in North Russia and Siberia. Women did their part overseas as telephone operators and American Red Cross volunteers.