This is a 1996 textbook. With the increasing complexity of processes to be analysed, the modern control engineer often needs to develop a model of the system to be controlled. However, in many cases, there is limited time for detailed system analysis, and the engineer may not be an expert in that particular system domain. This book is aimed at graduate engineers (and postgraduate students) who wish to use a systematic approach to model development that is suited to computer-aided modelling environments. The goal of this book is to support the use of modelling as a useful knowledge-enhancing exercise, and to propose corresponding modelling methodologies. The motivation for this is the widespread use of models in analysing and simulating systems for safe and cost-effective evaluation of new processes. The context is primarily that of control system design, due to the extensive use of models of the process, and its disturbances, in modern design methods. We use the term metamodelling to describe the approach taken; i.e. a modelling methodology which transcends the accepted mathematical models for specific applications. This methodology abstracts general models from first principles, by employing an existing notation (bond graphs) as a metalanguage for describing physical systems. This book is, therefore, concerned with separating out the model development process from the functions for which the model is developed, in order to enhance understanding of the essentials of the real physical systems. This book is organised in two parts, so that the reader may first understand the motivation and the basic concepts, and then have the proposed methodology illustrated by a variety of examples covering a wide selection of applications. The first part describes general modelling principles, based on system decomposition, first using classical dynamical analysis and then via the energy bond graph notation. Bond graphs are shown to provide a powerful core model representation from which a variety of mathematical models may be derived. Bond graphs provide a useful means of illustrating causality which is shown to be a crucial aspect of system modelling. The second part uses specific case studies to illustrate the application of this methodology to systematic generation of the most widely used mathematical models. Reference is made to a computer-aided modelling tool (MTT), which is a research modelling toolbox which uses bond graphs to support the modelling of dynamic processes. This textbook was originally published by Prentice-Hall in 1996. The rights were returned to the authors on 21st July, 2003.