This article explains how the Prince of Wales's interventions of the 1980s in architecture gave rise to his Institute of Architecture and his Urban Design Task Force (UDTF). It points out that both institutions were intended to foster closer dialogue between theory and practice, and to embed formal architectural and planning typologies in building process. A distinction is drawn between the approach of the UDTF and the 'urban village' thinking which underlies The Prince's Foundation (successor body to the Institute of Architecture). The Institute of Architecture and the UDTF were helped by the fact that Leon Krier and Christopher Alexander, respectively leaders of the formal and process-orientated (or 'structural') schools of urban design, supported their efforts. The unique encounter between the two suggested a 'Third Way' for urban propositions, able to mediate between political extremes (e.g. between historical reconstruction and a modernist tabula rasa ), and to provide clear formal strategies of an inclusive and broadly accessible kind. The article looks in detail at the 1997 UDTF in Lebanon-in which Samir Younés and Hajo Neis, acolytes of Krier and Alexander, worked on the design of a new urban quarter adjacent to the ancient city of Sidon-and estimates the value of the resulting dialectic between master plan and generative processes at work in the city. Also discussed are the nature of 'tradition', the meanings and limitations of the master plan document, the 'hidden hand' represented by latter-day building processes, and the value of 'restitution' as against 'restoration'. In conclusion it is asked how an 'urban renaissance' can be brought about in a period of economic and political liberalization.

The main tenets of the classical school of architecture and urbanism, now termed 'New Urbanism' in the USA, began to be laid down by the Luxembourg architect Léon Krier during the 1970s. The Krier approach was distinguished by its clarity, and matched by an extremely effective polemical strategy, in which many things which had been outlawed from urban design thinking since World War II were made to seem once again to be simple good sense.

The Krier approach relies upon cool, rational analyses of urban plans of all kinds, and a willingness to apply perennial strategies to a variety of situations. It seeks to define a town from the level of its pathways up to the boundaries of its urban quarters and beyond. Localized decisions about circulation routes and the urban 'grain' are always taken with the more global context in view, and vice versa.

Over the same period, two sets of design tools were being developed at the Center for Environmental Structure (CES) at the University of California at Berkeley. One set consists of the 253 generative patterns published in A Pattern Language (Alexander et al., 1977), a distillation of archetypes of spatial organization, based on empirical observation and discussion which have taken place all over the world.

The second, as yet less defined set, consists of the processes, or sequences, by which these patterns can be applied to specific building projects, defining the stages by which the parts are best added together. Research is still proceeding in this latter area, focusing on such topics as 'structure-preserving transformations', a term covering interventions which add to rather than substract from an emerging whole.

On the surface Krier's classical and Alexander's structural approaches seem to occupy two mutually exclusive worlds, even though the objective of both is to recreate the conditions which gave rise to the widely appreciated forms of the traditional environment. Clearly, there were important differences to be borne in mind, which are set out in the following page:

The classical and structural approaches to urbanism had generally been assumed to be irreconcilable, even by those with evident sympathy with both of them. Ingrid Fiksdahl King, who worked with Alexander on his most successful projects, tried (King, 1993) to place his philosophy in the context of other current theories about architecture and the city, including the notion of architectural typology - an explicit concern of the Krier school. She concluded that the distinction between Alexander and Krier was that the former welcomed innovation at the level of typology, while the latter dismissed it.

In fact, this is a wholly false notion of how typology is viewed by the Krier school, and possibly a too-relaxed view of the attitude of the Alexander school. Both, in fact, understand that type must evolve, and there must, therefore, be room for for typological innovation. The difference lies in what each considers to be the most appropriate channel for this innovation. Krier would argue that it must spring first from an intellectual act, while Alexander would expect it to emerge from practice, modified by constant use, like a language.

Two quotations will serve to sum up the different perceptions of a city's growth characteristic of these two schools of thought:

"...a perfectly 'just civic constitution', must be the supreme task nature has set for mankind... It takes the greatest want of all to bring men to the point where they cannot live alongside each other in wild freedom but within such an enclosure as the civic association provides. These very same inclinations afterwards have a very good effect.

 It is like the trees in a forest which, since each seeks to take the air and the sun away from the other, compel each other to seek both and thus they achieve a beautiful straight growth. Whereas those that develop their branches as they please, in freedom and apart from each other, grow crooked and twisted.

Emanuel Kant (1784), (Cited by Samir Younés in support of his Sidon Master Plan)

"When we say that something grows as a whole, we mean that its its own wholeness is the birthplace, the origin, and the continuous creator of its ongoing growth. That its new growth emerges from the specific, peculiar structural nature of its past. That it is an autonomous whole, whose internal laws, and whose emergence, govern its continuation, govern what emerges next. We feel this quality very strongly, in the towns which we experience as organic. To some degree we may know it is as a fact about their history. To some degree we can simply feel it in the present structure as a residue.

Kant's image is a memorable one, but the growth he dismisses as "crooked and twisted" becomes, in Alexander's more 'organic' view, the seed of a more compelling whole. The Urban Design Task Force sought union between the Law described by Kant (and espoused by the Krier school) and the Life beloved of Alexander, and hence between the city and nature (including human nature). Over the past decade it has become increasingly apparent that this is no trivial ambition, but one which is central to the new project of the human sciences. For example, Stuart Kauffman, one of the leading thinkers in the 'complexity sciences', has referred to the phase transitions seen in autocatalytic sets as offering "models [which] are the place for contingency and law at the same time".