This text provides a comprehensive review of the methodologies and applications of simulation and modelling. The methodology section includes such topics as: the philosophy of simulation; inverse problems in simulation; simulation model compilers; treatment of ill-defined systems; and a survey of simulation languages. The application section covers a wide range of topics, including applications to environmental management, biology and medicine, neural networks, collaborative visualization and intelligent interfaces. The book consists of 13 invited chapters written by former colleagues and students of Professor Karplus. Also included are several short "reminiscences" describing Professor Karplus impact on the professional careers of former colleagues and students who worked closely with him over the years.