In the world of advanced materials, cubic boron nitride is an active competitor for diamond, with similar properties. To develop advanced materials, it is essential to have characterization techniques, which reveal the structure and chemistry of the samples. Especially in the era of nanotechnology, techniques capable of high spatial resolution are required. This monograph addresses characterization of abrasive cubic boron nitride (ABN) particles by X-ray diffraction (XRD), electron microscopy (EM) and electron energy loss spectroscopy (EELS) in the STEM. XRD profiles of ABN samples are correlated with particle morphology and compositional variations. EELS in STEM is utilized to gain nanostructural information as well as electronic structure. Results are given showing anomalous surface structure-a layer of h-BN as well as oxidation, stoichiometry, and inclusions inside the particles. ELNES is revealed for c-BN, h-BN, and BC2N and are compared with ab-initio theory and with previously recorded results. The book should be especially useful for those researchers developing new materials as well as for those concerned with modern characterization techniques in materials science and EM.