Book excerpt: SF6 is a colorless, odorless, tasteless, non-toxic gas (down to -20 degrees C) which has nearly ideal properties as an arc-quenching medium. Ryan and Jones (electrical engineering, Sunderland Polytechnic and U. of Liverpool) review the characteristics of SF6, discuss arc modelling methods, its use in switchgears, operation of circuit breakers; and reflect upon its impact on regulations, testing and instrumentation. History and synthesis are neglected. Annotation copyrighted by Book News, Inc., Portland, OR