The emergence of applied mathematics as a discipline in the United States is traditionally associated with World War II. Hungarian-born Theodore von Kármán was among those who had waged a long and vigorous campaign well before the war to make applied mathematics respectable to engineers and mathematicians. While advocating the use of mathematics and physics to solve applied problems, he challenged the prevailing philosophy of engineering programs, locked horns with recalcitrant journal editors, and generally encountered the obstacles to building a discipline that cuts across conventional boundaries.