This tutorial covers the underlying theory behind SEM imaging and analysis. Practical 'tips and tricks' are provided to assist in using your SEM effectively. Although the primary focus will be on the theory, operation and value of the SEM, there will also be discussion of recent developments in high resolution electron microscopy to cope with the ever-shrinking dimensions encountered with semiconductor analysis. The limitations on resolution in the SEM will be discussed, and two methods will be presented which overcome these limitations and enable ultra-high resolution imaging: STEM-in-SEM and low-loss imaging. A new technology called Helium Ion Microscopy will also be discussed.