This Spotlight presents the state-of-the-art of aerosol remote sensing, including remote sensing principles and satellite- and ground-based approaches. The mechanism and theories are introduced along with the component mixing rules, e.g., Maxwell-Garnett, Bruggeman, and volume-weighted average approaches. Recent advances in aerosol-component methods are discussed, focusing on composition schemes, inversion methods, and validation results. The final section looks at the remote sensing applications of atmospheric aerosol composition and species.