Twenty of the 24 chapters in this power transformer handbook are revised versions of chapters published in the Electric power engineering handbook (2001). Nine of the chapters review the design, connection, operation, and performance testing of specific types of transformers, such as phase-shifting transformers, rectifier transformers, and step-voltage regulators. Other topics include insulating media, electrical bushings, load tap changers, transformer protection, the causes and effects of transformer sound levels, and online monitoring of liquid-immersed transformers.