The substantial collection of Wizard of Oz materials assembled by William Bromberg over the course of his life completes the already sizable holdings of Oziana in the Gildersleeve Collection of Children's Literature. The Bromberg collection includes the Oz books of Baum as well as the continuation of the series by other authors. There is also a substantial collection of secondary literature. The collection includes several rare novels by Baum that do not involve the Oz characters and a small collection of Oz ephemera. The collection has been cataloged in Connecticut College's Caravan system and may be retrieved by searching for William Bromberg Collection.

The collection was donated to Connecticut College by the estate of William Bromberg in 2008.