INTRODUCTION

ground, the reason is that materials can become architecturally
effective only-when the architect instils into them an aesthetic mean-
ing. Architecture is not the product of materials and purposes—nor
by the way of social conditions—but of the changing spirits of
changing ages. It is the spirit of an age that pervades its social life,
its religion, its scholarship and its arts. The Gothic style was not
created because somebody invented rib-vaulting. The Gothic spirit
existed and expressed itself in rib-vaults, as has been proved and will
be mentioned again later, before the constructional possibilities of
the rib had been discovered. The Modern Movement did not come
into being because steel-frame and reinforced-concrete construction
had been worked out—they were worked out because a new spirit
required them.

Thus the following chapters will treat the history of European
architecture as a history of expression, and primarily of spatial
expression.

E.A.—2 XXI