This practical book looks at the fundamental principles that underpin the process of architectural illustration: to represent architectural design and the built environment in a way that the general public can understand. Focusing particularly on watercolour, it explains the full process from site sketching to finished rendering. Case studies follow the process of an illustration, using demonstrations specially selected from the author's own work and profiles of leading practitioners. Detailed diagrams show how to set up a perspective drawing by hand and using 3D modelling. Illustrated with over 200 colour images, it is a unique guide to the work of the architectural illustrator and will be invaluable for artists, illustrators, architects, builders and planners.