From Hitchcock and Johnson, The International Style: Architecture Since 1922 (pp.20)

The new principles of architecture
¥ ÒThere is, first, a new conception of architecture as volume rather than as mass.  Secondly, regularity rather than axial symmetry serves as the chief means of ordering design.  These two principles, with a third proscribing arbitrary applied decoration, mark the productions of the international style.Ó