Electric motors make up a large portion of our global electricity consumption and have enjoyed a long history doing so. Electrical steels are popularly used materials in electric motors to improve their performance. This has made them prime candidates for increasing the energy efficiency of electric motors, especially given concerns regarding energy conservation. Now manufacturers of electrical steels have been prompted to seek increasingly efficient electrical steels to provide a more competitive product. This literature review focuses on one specific metallurgical aspect – the defining trait of electrical steels; silicon content and its resulting influence on the physical properties. From the literature review it is concluded that the application requirement and functionality must be considered thoroughly when deciding silicon content. This review was submitted as part of the 2017 Materials Literature Review Prize of the Institute of Materials, Minerals and Mining run by the Editorial Board of MST. Sponsorship of the prize by TWI Ltd is gratefully acknowledged