Part 1 The nature of modelling: computational issues in modelling, Jon Ogborn and Rob Miller; representations and representation systems, Haralambos Sakondis. Part 2 Mathematics and reality: reasoning with a quantitative modelling tool, Richard Boohan and Tim Brosnan; integrating situated-based and algebraic approaches - the role of spreadsheets, Rosamund Sutherland; models and metaphors in reasoning about probability, Peter Wilder. Part 3 Commonsense reasoning about quantities: reasoning with a semi-quantitative tool, Joan Bliss. Part 4 Thinking with objects, links and logic: an introduction to qualitative modelling tool, Joan Bliss and Haralambos Sakondis; creating worlds with objects and events, Richard Boohan.