The XSQR technique uses nearly monoenergetic X-rays from the proton bombardment of a primary target to excite X-ray fluorescence for analytical purposes. With the proper choice of primary target, interferences from high concentration components in a matrix may be eliminated. An overview is given of the technique, the equipment it uses and its methodology. The application of the technique is described for the determination of Cr in steels using an Fe primary, Cu and Zn in gold objects using a Ge primary, multielemental analysis of geological and biological materials using primary targets such as Mo, Rh and Pd and Si in oils using a Ti primary target. The method serves as a useful complementary method to PIXE for the determination of the medium mass elements.