"This book is intended to give the theoretical foundation of the electromagnetic time reversal theory. Special emphasis is given on real applications in the fields of EMC and power systems"--Abstract: The aim of this book is to familiarize the reader with the concept of electromagnetic time reversal, and introduce up-to-date applications of the concept found in the areas of electromagneticcompatibility and power systems.The basic idea of the EMTR is to take advantage of the re-versibility in time of the wave equation. The transients observedin specific observation points of the system are time-reversedand transmitted back into the system. The time-reversed signalsare shown to converge to the source (fault) location. The EMTRpresents several advantages.Typical methods used these days are based onthe estimation of the postfault impedance observed in measurement points usually located in primary substations. Withthe hypothesis of having a fully passive power system, such an es-timation could provide useful information to locate the faultwhen compared with the line impedance. However, the presence of other sources (e.g., associated with the increasing pen-etration of dispersed generation) can largely affect the accuracy of these procedures. For these reasons, procedures that belong to the second of the aforementioned categories may be less influenced by the presence of dispersed generation. Thisis because postfault high-frequency electromagnetic transientstaking place within the first few milliseconds after the fault areassociated with the travelling waves originated by the fault it-self. Therefore, these transients are not influenced by the industrial frequency power injections of distributed sources. Themajor drawbacks of this second category of methods are: 1) theyrequire an assessment between the number of observation pointsversus the number of possible multiple fault-location solutionsand 2) they require large bandwidth measuring systems.Within this context and by referring to the second of the afore-mentioned categories, this paper aims at investigating the pos-sibility of applyingthe theory of time reversal to the problemof fault location.This method was developedfirst in thefield of acoustics [15]–[18] and was more recently applied to electromagnetics