The Sixth Edition contained over 20,000 entries and was overseen by Peter N. Stearns.

An Encyclopedia of World History: Advanced, Medieval, and Modern, Chronologically Arranged.

Compiled and Edited by William L. Langer, Coolidge Professor of History, (Emeritus by 1968), Harvard University.

The Encyclopedia of World History: Ancient, Medieval, and Modern, chronologically arranged.

A completely revised and updated edition of the classic reference work originally compiled and edited by William L. Langer.