This book is the fruit of a very long and elaborate process. It was conceived as a comprehensive solution to several deficiencies encountered while trying to teach the essentials of Computer Vision in different contexts: to technicians from industry looking for technological solutions to some of their problems, to students in search of a good subject for a PhD thesis, and to researchers in other fields who believe that Computer Vision techniques may help them to analyse their results. The book was carefully planned with all these people in mind. Thus, it covers the fundamentals of both 2D and 3D Computer Vision and their most widespread industrial applications, such as automated inspection, robot guidance and workpiece acquisition. The level of explanation is that of an expanded introductory text, in the sense that, besides the basic material, some special advanced topics are included in each chapter, together with an extensive bibliography for experts to follow up. Well-known researchers on each of the topics were appointed to write a chapter following several guidelines to ensure a consistent presentation throughout. I would like to thank the authors for their patience, because some of them had to go through several revisions of their chapters in order to avoid repetition and to improve the homogeneity and coherence of the book. I hope they will find that the final result has been worth their efforts.