Columbia Encyclopedia. Sixth edition
The is a one-volume encyclopedia produced by Columbia University Press and in the last edition, sold by the Gale Group. First published in 1935,and continuing its relationship with Columbia University, the encyclopedia underwent major revisions in 1950 and 1963; the current edition is the sixth, printed in 2000. It contains over 51,000 articles totaling some 6.5 million words and has also been published in two volumes.