I present a comprehensive study on the nature of the SDSS galaxies divided into fine classes. Based on their morphology, color and spectral features, the SDSS galaxies are classified into early-type and late-type; red and blue; passive, HII, Seyfert and LINER, which returns a total of 16 fine classes of galaxies. I compare the photometric, structural and spectral properties of those galaxies between the fine classes using multi-wavelength data, and investigate their local environments such as local density, local color and close pairs. I introduce several important findings and discuss their implication on galaxy evolution.