This digital edition is an expanded and updated version of the long out-of-print Columbia Phonograph Companion, Volume II. The digital edition utilizes the format introduced in the print edition, where each model of Columbia's disc line was featured on it's own full page,. Each model is illustrated with a large image, usually from original Columbia literature, and a description giving the pertinent details. New to this digital edition is the addition of supplemental images and details that may be viewed by tapping on the catalog image. This edition has been expanded with the addition of several models that were not included in the print edition.