In 1935, the Wagner Collection joined the Mason Collection as an important collection of Western Americana. At this time Henry Raup Wagner gave to Pomona College his collection of books and maps assembled in preparation for his Cartography of the North West Coast of America to the Year 1800, a work published by the University of California Press in 1937. This consisted of 629 maps, most of them photostats, but containing in all every map made before 1800 that Wagner could find which showed the North Pacific Coast. Now, some of these photostats are the only evidence that a certain few maps ever existed, as the maps themselves no longer exist or are missing. With the maps came about six hundred books, some published as early as the sixteenth century, dealing with geography, navigation, and naval architecture. The Wagner gift also included a number of volumes in which he had bound together photostats of manuscripts, translations, and the text which he had prepared based on the sources. These were the accounts of voyages which were published under the title: Spanish Voyages to the Northwest Coast of America in the Sixteenth Century.