2015 Elsevier Ltd. All rights reserved. Clouds constitute a unique and important component of the atmosphere. This article briefly reviews the methods of inferring cloud-top height, determining cloud thermodynamic phase, and retrieving cloud microphysical and optical properties (specifically, the effective particle size and optical thickness). Some examples based on observations made by a passive spaceborne sensor (the Moderate Resolution Imaging Spectroradiometer) and an active spaceborne sensor (the Cloud-Aerosol Lidar with Orthogonal Polarization) are illustrated.