This book discusses information modelling combined with a description of the express information model specification language. EXPRESS is a new language that when used with information modelling abstracts away the implementation bias prevalent in current data modelling technology.One of the main tenets of EXPRESS is that a clear separation exists between the information model and the information system environment - a piece of information is not tied to a single application that uses it. The book will be of interest to data and information modellers in both universities and businesses, especially those concerned with object-oriented systems as it illustrates the development and use of information models using EXPRESS.