Issued on November 2, 1944, under the direction of General Douglas MacArthur's General Headquarters, Southwest Pacific Area (SWPA), Terrain Handbook 39: Tarlac-Dagupan (Central Luzon) served as a vital intelligence document prepared for Allied field officers advancing through the Philippines during World War II. Compiling exhaustive data on roads, airfields, topography, water resources, communications, and local population centers, the handbook was designed to facilitate Allied tactical movement, logistics, and offensive planning across northern Central Luzon—a region of paramount strategic importance that controlled land routes leading north from Manila.
The military intelligence encapsulated in this volume directly laid the groundwork for the Lingayen Gulf landings in January 1945 and the subsequent liberation of Luzon from Japanese occupation. Beyond its immediate tactical utility, the handbook preserves a detailed historical, infrastructure, and socio-geographic profile of Pangasinan, Tarlac, and Nueva Ecija during the late occupation era.