Carbon materials have industrial applications owing to their excellent features such as electrical conductivity, chemical and thermal stability, light weight, and low cost of preparation. Nevertheless, the actual structures of carbon materials have not been well documented until recently, except for their chemical composition. Recent developments in analytical technologies for probing the structure of carbon materials, such as transmission electron microscopy, Raman spectroscopy, and high-sensitivity temperature-programmed desorption methods, have enabled understanding of the actual three-dimensional (3D) structure of carbon materials at the molecular and atomic levels.