A Pattern Language

Alexander and colleagues at the Center for Environmental Structure present two hundred and fifty-three patterns for building at every scale, from the organisation of regions and towns down to the placement of a window seat. Each pattern has the same structure: a name, a photograph, a statement of the problem, the body of evidence and reasoning, the solution stated as an instruction, and links to the larger patterns it helps complete and the smaller ones needed to complete it.

The patterns are ordered by scale, beginning with independent regions, city country fingers and the distribution of towns, moving through neighbourhood patterns including identifiable neighbourhood and four-storey limit, to building patterns including light on two sides of every room, alcoves, entrance transition and common areas at the heart, and ending with construction details.

The underlying argument is that ordinary people, rather than professional architects, should shape the places they live, and that a shared language of patterns makes that possible. Alexander's claim is that traditional building produced good places because such languages existed and were widely held, and that professionalisation destroyed them.

The evidence for individual patterns varies enormously. Some cite research, some cite observation, and some are assertion. Architects have criticised the book for prescriptiveness and for its hostility to the profession. Its largest influence has been outside architecture entirely: the software design patterns movement took its structure directly from this book, and the wiki was invented by Ward Cunningham to hold a pattern language. Read it for the method of stating a recurring problem with a tested solution and for the specific building patterns, which are unusually concrete.