With the continued rapid growth of the internet and information sharing there is considerable interest in computerised personal identity verification. In particular "biometrics", a branch of identification that deals with verifying physical or behavioural characteristics of human beings, provides effective and powerful techniques for this purpose. This book is concerned with the development of the particular biometric of handwritten signature verification, which is superior in many ways to other biometric authentication techniques that may be reliable but are much more intrusive. Two primary modelling techniques are studied, providing both a sound basis for understanding of the complicated artificial intelligence and statistical methods of neural networks and hidden Markov models, as well as a detailed exploration of their application to handwritten signature verification.