International priests have served the Roman Catholic Church in the United States since its inception. With congregations consisting largely of immigrants or Spanish and French speaking Catholics absorbed by the expansion of US territory, it was only natural that the clergy reflected the remarkable mixture of ethnicities in the Church. New communities lacked the 'home-grown' vocations of more established communities, and the nascent Church needed to recruit or welcome priests and religious from other countries and cultures. It is for these priests and their missionary zeal that this book came to be.