The Book of Knowledge was an encyclopedia aimed at juveniles first published in 1912, by the Grolier Society.
Originally largely a reprint of the British Children's Encyclopaedia with revisions related to the United States by Holland Thompson, over time the encyclopedia evolved into a new entity entirely.
It was published under a policy of continuous revision, meaning that there were no separate editions, but annual printings that were edited and updated by the publisher.
[3] From 1949 Grolier also issued a Book of Knowledge Annual.
[4] Encyclopaedia Britannica praised the index system that was introduced by the Book of Knowledge: "much of the success of the work as a reference tool resulted from its splendidly contrived index, which remains a model of its kind.".