This work was supported primarily by the MRSEC program of the National Science Foundation under DMR-0079996. A method for the retrieval of the complete grain boundary character distribution by oblique double-sectioning is proposed. The method, which is similar to the recovery of the orientation distribution from sets of incomplete pole-figures, is efficient and provides many advantages as compared to calibrated serial sectioning. As compared to standard stereological approaches, the new methodology retains the advantage of direct measurement of the grain boundary inclination parameters. Solutions to the fundamental equation of oblique double-sectioning are provided in the Fourier space, and some specifics in sample preparation are introduced.