Neville R. Watson received BE(Hons.) and PhD degrees in 1984 and 1988, respectively, from the University of Canterbury, New Zealand, where he is now a senior lecturer. He is co-author of three other books, has contributed several chapters to a number of edited books and has been published in nearly 120 other publications.Jos Arrillaga received PhD and DSc degrees in 1966 and 1980, respectively, from UMIST, Manchester, UK, where he led the Power Systems Group between 1970 and 1974. Since 1975, he has been a Professor of Electrical Engineering at the University of Canterbury, New Zealand. He is the author of five other books, several book chapters and about 300 other publications. He is a Fellow of the IET, the IEEE, the Academy of Sciences of New Zealand and the Royal Society of New Zealand. He was the recipient of the 1997 Uno Lamm medal for his contributions to HVDC transmission.