The first edition of GaN Transistors for Efficient Power Conversion was self-published by EPC in 2012, and is currently the only other book to discuss GaN transistor technology and specific applications for the technology. More than 1,200 copies of the first edition have been sold through Amazon or distributed to selected university professors, students and potential customers, and a simplified Chinese translation is also available. The second edition has expanded emphasis on applications for GaN transistors and design considerations. This textbook provides technical and application-focused information on how to design efficient power conversion systems using gallium nitride (GaN) transistors. As a practical guide for power systems design, it provides background on the basic technology, performance specifications and insights on the use of GaN transistors in power electronics applications, ranging from existing power conversion circuits such as buck converters, to GaN FET enabled wireless power transfer and envelope tracking applications. There is coverage on fundamental power engineering subjects such as performance characteristics of GaN transistors, layout considerations for circuits using GaN FETs, and driver IC requirements for GaN transistors. Following these introductory chapters, the final chapters address specific applications for GaN devices as well as their future development and use in power electronics.