We present near-infrared spectra of the excess continuum emission from the innermost regions of classical T Tauri disks .
In almost all cases , the shape of the excess is consistent with that of a single-temperature blackbody with T \sim 1400 K , similar to the expected dust sublimation temperature for typical dust compositions .
The amount of excess flux roughly correlates with the accretion luminosity in objects with similar stellar properties .
We compare our observations with the predictions of simple disk models having an inner rim located at the dust sublimation radius , including irradiation heating of the dust from both the stellar and accretion luminosities .
The models yield inner rim radii in the range 0.07-0.54 AU , increasing with higher stellar and accretion luminosities .
Using typical parameters which fit our observed sample , we predict a rim radius \sim 0.2 AU for the T Tauri star DG Tau , which agrees with recent Keck near-infrared interferometric measurements .
For large mass accretion rates , the inner rim lies beyond the corotation radius at ( or within ) which magnetospheric accretion flows are launched , which implies that pure gaseous disks must extend inside the dust rim .
Thus , for a significant fraction of young stars , dust can not exist in the innermost disk , calling into question theories in which solid particles are ejected by a wind originating at the magnetospheric radius .