The recognition of symbols in graphic documents is an intensive research activity in the community of pattern recognition and document analysis. This book entails the most outstanding symbol recognition methods from different points of view. Open and unaddressed problems involved in symbol recognition are described, analyzing their current state of art and discussing future research challenges. Thus, issues such as symbol representation, matching, segmentation, learning, scalability of recognition methods and performance evaluation are addressed in this book. The book enlightens the reader with the historical perspectives, applications, challenges and techniques of OCR. Various techniques have been used or simply proposed, during the last 10 years, for recognizing symbols in documents.