This paper reviews the history, chemistry, safety, toxicity, and anticancer effects of the organogermanium compound bis (2-carboxyethylgermanium) sesquioxide (CEGS). A companion review follows, discussing the inaccuracies in the scientific record that have prematurely terminated research on clinical uses of CEGS. CEGS is a unique organogermanium compound first made by Mironov and coworkers in Russia and, shortly thereafter, popularized by Asai and his colleagues in Japan. Low concentrations of germanium occur in nearly all soils, plants and animal life; natural occurrence of the CEGS form is postulated but not yet demonstrated. The literature demonstrating its anticancer effect is particularly strong: CEGS induces interferon-gamma (IFN-gamma), enhances natural killer cell activity, and inhibits tumor and metastatic growth--effects often detectable after a single oral dose. In addition, oral consumption of CEGS is readily assimilated and rapidly cleared from the body without evidence of toxicity. Given these findings, the absence of human clinical trials of CEGS is unexpected. Possible explanations of why the convincing findings from animal research have not been used to support clinical trials are discussed. Clinical trials on CEGS are recommended.