100 new books a year, and had annual sales of $4.5 million. In 1995, Dan Ross took over as UNP's fourth director, expanding Bison Books to focus on sports books, especially baseball, resulting in UNP's highly regarded publishing program in sports. That same year UNP's annual sales topped $6 million, a 600 percent increase from 1980. By the early 2000s, Gary Dunham took over as director and in 2009 UNP sold its longtime warehouse in the Haymarket. With Donna Shear as editor-in-chief, Bison Books was redefined to solely represent books of the west and UNP in general switched to a print-on-demand model of publishing, coordinating the simultaneous release of e-books with the print editions. Shear also tripled journal production to 30 publications and in September 2011 the press entered into a collaborative publishing arrangement with the Jewish Publication Society, one of the oldest Jewish publishers in the United States. In April 2013, the press acquired Potomac Books, a publisher specializing in military and diplomatic topics. With the new additions, UNP surpassed $7 million in sales in 2015, moved up in status with the American Association of University Presses, and become the 12th largest university press in the country. Since 2010, two of the press' books have received the Bancroft Prize, the highest honor bestowed on history books in the U.S. Imprints Nebraska Under its Nebraska imprint, UNP publishes both scholarly and general interest books, with a particular focus on Native and Indigenous studies, history, sports history, American studies and cultural criticism, environmental studies, anthropology, and creative works. UNP publishes scholarly editions of the works of Willa Cather, including the classics My Ántonia and O Pioneers!. Bison Books Bison Books began in 1961 as UNP's first trade imprint and originally focused on inexpensive paperbacks of general-interest works in Western Americana. In 2013 Bison Books shifted its focus to the trans-Mississippi West. The imprint has featured the work of notable authors such as André Breton, George Armstrong Custer, William F. Cody, Loren Eiseley, Michel Foucault, Che Guevara, Wright Morris, Tillie Olsen, Mari Sandoz, Wallace Stegner, Leo Tolstoy, Philip Wylie, and Stefan Zweig. Potomac Books Potomac Books began in 1983 as Brassey's, Inc., the U.S. imprint of a longstanding British publishing enterprise that focused on military subjects. The trade imprint was then acquired by Books International in 1999 and renamed Potomac Books in 2004, expanding its catalog to include world and national affairs,