This presentation covers the principles of STEM-in-SEM technology and its application in materials research and failure analysis. Part 1 describes the arrangement and function of major components in TEM-in-STEM systems, compares and contrasts imaging modes, and explains how different types of images are obtained by adjusting imaging parameters. Part 2 covers the implementation and use of 4D STEM-in-SEM. It provides examples showing how the method is used to examine diffraction patterns, capture images of materials susceptible to low-energy beam damage, and produce nanoscale strain, grain orientation, and temperature maps. It also includes a wide range of images obtained using a programmable STEM detector.