This article summarizes the work of the author’s lab based on crystallography. The topics are categorized in the following three fields: The first category is crystallographic analysis of materials, the second one is correlations between crystal structure and their properties, and the third one is crystallography for processing such as epitaxy, topotaxy and templates. The examples for these categories are: (1) multilayer ceramic capacitor (MLCC); (2) microwave dielectrics of tungstenbronze-type like solid solutions, and piezoelectric materials langasite (La3Ga5SiO14); (3) thin film growth of GaN or AlN on sapphire for example of epitaxy, hydroxy-apatite grown on diopside for topotaxy, and template growth of microwave dielectrics for template. Crystallography is useful in all studies, but is not almighty. Interdisciplinary study between crystallography and solid state physics is necessary to make clear the mechanism of the properties.