In this, the second Homo Faber book about architectural models, the focus is on the role that models play in representing ideas or concepts. For a person who has not been educated in architecture or design the very thought that models can exist, for some purpose other than to prefigure a completed building, is probably a surprise. Yet, every architect and architecture student learns that models can express a range of themes, ideas and desires none of which are necessarily constructable or even prefigure a design solution. Few of these models are ever seen by the general public and it is rare that an opportunity arises to gain a more detailed level of understanding about their production, application and meaning. This book explores the creation and use of architectural 'idea' or 'concept' models in the design process.