The proposed research aims to create the largest modern catalog of spiral galaxies with measured properties of their three-dimensional (3-D) structure. The structural properties will include parameters of the stellar disks, bulges, and dust medium. The catalog consists of visually confirmed, true edge-on disk galaxies, which will be selected from the Sloan Digital Sky Survey. The galaxies will be classified into distinct morphological types using a computer algorithm. The structural parameters will be measured using 3-D decomposition techniques, which involve radiation transfer models in order to account for the dust distribution in the galaxies. The ultimate goal of this research is to include an extra dimension--the vertical scale height of stellar disks and bulges--to the scaling relations for disk galaxies and their Dark Matter halos. The scaling relations will provide a framework for testing cosmological models of disk and bulge formation. In combination with growing, multi-wavelength data sets coming from ongoing large surveys, the catalog will provide a solid background for advanced structural studies of spiral galaxies.