This exhibition at the Library of Congress was intended on the part of the Vatican Library, at a distance of over sixty years, to express its gratitude to all those from North America who contributed so forcefully to "the common convenience of the learned" which is at the heart of the Vatican Library--to the Carnegie Endowment and Nicholas Murray Butler, to the University of Michigan Library School at Ann Arbor and William Warner Bishop, and above all, given the location of the exhibition, to the Library of Congress and Hserbert Putnam and Charles Martel