A Pattern Language: Towns, Buildings, Construction is a 1977 book on architecture. It was authored by Christopher Alexander, Sara Ishikawa and Murray Silverstein of the Center for Environmental Structure of Berkeley, California, with writing credits also Max Jacobson, Ingrid Fiksdahlt and Shlomo Angel. It is the sequel to The Timeless Way of Building.
The book is a substantive, illustrated discussion of a pattern language derived from traditional architecture , with about 250 unitary patterns such as Main Gateways given a treatment over several pages.
The trilogy was completed by The Oregon Experiment.