Glass containing cobalt has been discovered from the Babylonian-Assyrian period, the Mycenaean era, and the Roman Empire. Commercially, cobalt was not used as a glass colorant until the late 1800s. Small quantities of cobalt were produced by American glass companies from the late 1800s to the mid-1920s. Most of the American cobalt glass in this book is from the mid-1920s to World War II. Several companies including the Hazel-Atlas Glass Company, the L.E. Smith Glass Company, and the MacBeth-Evans Glass Company produced machine-molded cobalt glass during the 1930s that can be considered true Depression glass. Many of the major glass companies are covered in this book: Cambridge, Central Glass, Duncan & Miller, Fostoria Glass, Hazel Atlas, A.H. Heisey, Imperial, Paden City, Westmoreland, and many more. There are over 800 color photos. Items shown include candlesticks, bowls, compotes, cake stands, trays and platters, glasses, pitchers, and perfumes. 2009 values.