Array tomography is a volumetric microscopy method based on physical serial sectioning. Ultrathin sections of tissue are cut using an ultramicrotome, and attached in order to a glass coverslip. These coverslips are then stained as desired and imaged. The resulting two-dimensional image tiles can then be reconstructed computationally into three-dimensional volume images for visualization and quantitative analysis. The thin sections allow for rapid staining and imaging and the array format allows much of the process to be automated. In the November issue of Cold Spring Harbor Protocols, Stephen J. Smith and colleagues from Stanford University present Array Tomography: High-Resolution Three-Dimensional Immunofluorescence, a guide to this technique that allows for visualizing previously inaccessible features of tissue structure and molecular architecture. As one of November’s featured articles, it is freely accessible to subscribers and non-subscribers alike.