In this paper we will provide a brief review of our recent investigations of the physical and chemical properties of transition metal carbides and nitrides using the near-edge X-ray absorption fine structure (NEXAFS) technique. We will first use single crystal model surfaces to demonstrate the capabilities of NEXAFS for determining fundamental electronic and structural properties of transition metal carbides and nitrides, such as the ionicity of the metal-nonmetal bonds, the p-projected density of unoccupied states, and the location of carbon and nitrogen atoms on the surface or interstitial subsurface sites. We will use several examples to correlate these electronic and structural properties to the chemical reactivities of the transition metal carbide and nitride model surfaces. Furthermore, we will compare the general similarities of the NEXAFS investigations between model surfaces and powder catalysts. We will also provide several examples to demonstrate how the fundamental learnings from the model surfaces can be used to understand the catalytic properties of powder materials with complicated catalytic formulations, such as the bimetallic oxycarbide and oxynitride catalysts.