Most of the interesting and difficult problems in statistical mechanics arise when the constituent particles of the system interact with each other with pair or multi particle energies. The types of behaviour which occur in systems because of these interactions are referred to as cooperative phenomena giving rise in many cases to phase transitions. This book and its companion volume (Lavis and Bell 1999, referred to in the text simply as Volume 2) are princi pally concerned with phase transitions in lattice systems. Due mainly to the insights gained from scaling theory and renormalization...