2017 is the 50th anniversary of the discovery of fast ion transport in beta-alumina. This discovery led to a revolution in the study of solid materials that might exhibit ionic motion as fast as that found in liquids. The need for materials with both fast ionic and electronic conductivity and a wide stoichiometry range to measure the ionic conductivity of beta alumina led to the intercalation concept for rechargeable alkali metal batteries. These discoveries and the resulting development of the lithium battery are described.