In a recent issue of Vision Research. Mayhew and Frisby (1982) raise a number of questions concerning our recently-presented theory of the induced size effect (Arditi et al., 1981). The basis of our theory is a simple one: that the apparent depth in the induced effect is a consequence or the horizontal disparity produced in the images of obliquely-oriented contours by the geometry of vertical magnification. Mayhew and Frisby correctly point out some errors in the original exposition of our theory, but erroneously state that their objections are "insuperable".