general encyclopaedia first published in 1950–51 in the United States and continuously revised. Originally in 20 volumes, Collier's was expanded to 24 volumes for a major revision in 1962. It is a well-reputed work with coverage reflecting secondary-school and college curricula. Its style is concise and readable. Most of the articles are signed, many by world-renowned scholars.

Collier's is strongest in its treatment of the arts and humanities, social sciences, and botany. Major biographies receive lengthy treatment; geography articles are attractively presented and receive a high percentage of the set's space. Accompanying illustrations, well-reproduced, include effective graphics, photographs, diagrams, and drawings.

Volume 24 contains bibliographies arranged under broad subject headings with various subdivisions; a study guide, which lists the articles in the encyclopaedia that the editors consider fundamental to a thorough understanding of a given subject; and an exhaustive, consolidated index to text, illustrations, maps, and bibliographies.