We present an analysis of the disk brightness profiles of 218 spiral and lenticular galaxies. At least 28% of disk galaxies exhibit inner truncations in these profiles. There are no significant trends of truncation incidence with Hubble type, but the incidence among barred systems is 49%, more than 4 times that for nonbarred galaxies. However, not all barred systems have inner truncations, and not all inner-truncated systems are currently barred. Truncations represent a real dearth of disk stars in the inner regions and are not an artifact of our selection or fitting procedures nor the result of obscuration by dust. Disk surface brightness profiles in the outer regions are well represented by simple exponentials for both truncated and nontruncated disks. However, truncated and nontruncated systems have systematically different slopes and central surface brightness parameters for their disk brightness distributions. Truncation radii do not appear to correlate well with the sizes or brightnesses of the bulges. This suggests that the low angular momentum material apparently missing from the inner disk was not simply consumed in forming the bulge population. Disk parameters and the statistics of bar orientations in our sample indicate that the missing stars of the inner disk have not simply been redistributed azimuthally into bar structures. The sharpness of the brightness truncations and their locations with respect to other galactic structures suggest that resonances associated with disk kinematics, or tidal interactions with the mass of bulge stars, might be responsible for this phenomenon.