The term "neural networks" is used to describe a number of different models intended to imitate some of the functions of the human brain, using certain of its basic structures. The authors aim to convey an intuitive and practical understanding of the topic and to provide the foundations necessary before undertaking further study. To this end, the first part of the book is devoted to a description of biological foundations. Biology is the source of study of neural networks and it seems probable that it will continue to provide a source of essential ideas. Following this introduction, a general model for neural networks is presented and a number of today's most important models are studied. Lastly, a number of real applications are discussed.