As one of the many by-products of Moore’s Law, personal computers have, in recent decades, become powerful enough to record real-time eye movements with video-based eye trackers. The decrease in the prices of eye tracking systems (ETSs) has been accelerating since the 1990s, and their use in a variety of scientific domains expanding. ETSs and related applications have shown a lot of promise in recent years, and their widespread and ever-increasing use in mainstream/personal equipment for daily life has transformed them from a novelty into a relatively common tool.This book showcases the state of the art in current eye tracking research by bringing together work from a wide range of application areas. It grew out of the 3rd International Conference on Eye Tracking, Visual Cognition and Emotion (ETVCE 12), held at the Lusophone University, Lisbon, Portugal (October 2012). This book provides an overview of the latest research in a broad range of disciplines for which eye-movement is relevant, and will inspire the intersection of knowledge between these areas. However, this is not a book of Proceedings. Rather, it is an edited, peer-reviewed selection of chapters based on presentations at the conference, and also includes invited chapters by authors who were not able to attend the conference. The efforts of these contributors have resulted in a state-of-art book which will inspire and guide students, lecturers, researchers and developers in eye-tracking research, and stimulate the use of eye-tracking across scientific disciplines.