Garden design theory explains, or should explain, the 'What, Where, Why and How' of making gardens.

Many of the world's best-designed cities have been inspired by garden concepts.

Humphry Repton, the leading garden theorist of the nineteenth century, defined a garden as 'a piece of ground fenced off from cattle, and appropriated to the use and pleasure or man: it is, or ought to be, cultivated and enriched by art'.

Having lasted for 4,000 years, the use of nature's materials to express ideas about nature may be expected to continue. The best garden designs are produced with an awareness of the art, science, history, geography, philosophy, social habits and construction techniques of their period.

In ancient times the ritual, mythological and doctrinal aspects of spiritual space were predominant.

In town and in country there must be landscapes where we can walk in safety, pick fruit, cycle, work, sleep, swim, listen to the birds, bask in the sun, run through the trees and laze beside cool waters.

There is much to learn about what could happen in the gardens of the future, should designers wish to learn about the past.