There are too few authors who reflect on the act of designing. Generally designers, when they publish, like to show off the designs they have made. One time-honored way of instructing in design is by exemplar – the case history approach. Another approach takes so-called ‘principles’ – usually rules of thumb – which have worked in the past (in most cases). Two centuries ago, the architect Rondelet wrote: “Théorie est une science qui dirige toutes les opérations de la pratique.” (Rondelet, 1830) Two millenia ago, the Vitruvian vision was one in which architect and engineer were indistinguishable (Vitruvius, 1914). While today that is generally speaking no longer the case, it gives me special delight to introduce a book on design where the authors hail from both disciplines: authors who, often in lonely circumstances, are contributing to the development of theoretical foundations for the act of designing. Their otherwise separate and isolated efforts are brought together between these covers by two distinguished editors. It is this confluence of ideas that impresses: perhaps, a trickle now, but a potential torrent tomorrow.

There is an apt quotation by Machiavelli that heads the Preface. In the case of theoretical contributions to design, history confirms a persistent resistance to change. Girard Desargues is a good example (Desargues, 1636, 1639; Field and Gray, 1987). He reflected upon the spatial representations that engineers and architects, such as himself, employed when designing.