In recent years, Bayesian methods have become the most widely used statistical methods for data analysis and modelling. The BUGS software has become the most popular software for Bayesian analysis worldwide. Authored by the team that originally developed this software, The BUGS Book provides a practical introduction to this program and its use. The text presents complete coverage of all the functionalities of BUGS, including prediction, missing data, model criticism, and prior sensitivity. It also features a large number of worked examples, covering a wide range of applications from various disciplines, and exercises, solutions, code and data on a supplementary website.