Music of the tonal period generally begins and ends in the same key, although passing through other keys in the course of a movement. Theorists of music generally ascribe great significance to such large-scale tonal closure. In order to test the effect of such closure upon aesthetic response, listeners were required to evaluate a number of compositions in two versions, one of which was in each case tonally closed while the other was not. The results indicate that the direct influence of tonal closure on listeners' responses is relatively weak and is restricted to fairly short time spansmuch shorter than the duration of most tonal compositions. Although large-scale tonal structure may not in itself be perceptible, it plays an important role as a means of compositional organization, and it is argued that the theory of tonal music is more usefully regarded as a means of understanding such organization than as a means of making empirically verifiable predictions regarding the effects of music upon listeners.