A summarizing account is given of the research on barium titanate in progress at the Laboratory for Insulation Research at M. I. T. since 1943. The investigations have led to an understanding of the mechanism of ferroelectricity in the titanates and to discoveries such as the piezoelectric effect in the ceramics and the domain structure of the single crystals of BaTi${\mathrm{O}}_3$. The high dielectric constant, field strength and temperature sensitivity, and piezo-response of the barium titanate dielectrics make them useful for numerous technical applications.

DOI:https://doi.org/10.1103/RevModPhys.22.221