The Debye microdiffractometer, a recently developed instrument, enables diffraction patterns to be obtained from very small samples or from selected areas of samples. The instrument discussed here, a Rigaku Model 2870E1 microdiffractometer, features an annular sealed proportional counter which is moved along the primary beam axis for two theta scanning, as seen in Figure 1, This configuration allows most of a Debye cone to be detected, making the use of a primary bean typically less than 100 microns in diameter practical. An integral microscope facilitates sample positioning for diffraction from selected areas of a specimen. The capability of the Instrument is apparent from the diffractometer traces of Figure 2, in which intermetallie compounds in a braze joint are identified.