The disk positions for galaxies of various morphological and nuclear-activity types (normal galaxies, QSO, Sy, E/S0, low-surface-brightness galaxies, etc.) on the mu(0)-h (central surface brightness-exponential disk scale) plane are considered. The stellar disks are shown to form a single sequence on this plane (SB0 = 10(-0.4 mu 0) infinity h(-1)) over a wide range of surface brightnesses (mu(0)(I) approximate to 12-25) and sizes (h = 10-100 kpc). The existence of this observed sequence can probably be explained by a combination of three factors: a disk-stability requirement, a limited total disk luminosity, and observational selection. The model by Mo et al. (1998) for disk formation in the CDM hierarchical-clustering scenario is shown to satisfactorily reproduce the salient features of the galaxy disk distribution on the mu(0)-h plane. (C) 2000 MAIK "Nauka/Interperiodica".