This chapter will introduce the analyst to scanning/transmission electron microscopy (STEM/TEM). Basic concepts required for understanding scanning/transmission electron microscopy will be given. Simple introduction of TEM instrumentation, specimen preparation, and basic TEM operation will be discussed from the perspective of the instrument user. Diffraction will cover selected-area diffraction, nano-beam electron diffraction, and convergent-beam electron diffraction. Several typical TEM imaging techniques such as thickness-mass contrast imaging, diffraction contrast imaging, weak-beam dark-filed TEM imaging, high-resolution TEM imaging, energy-filtered TEM imaging will be presented. STEM imaging techniques will include high-angle annular dark-field imaging, STEM-bright-field imaging, and annular bright-field imaging. Spectroscopy (including energy-dispersive spectroscopy and electron energy-loss spectroscopy), energy-filtered TEM imaging and spectrum imaging will be described in a practical way. Aberration-corrected STEM/TEM including high-angle annular dark-field imaging and annular bright-field imaging, negative Cs TEM imaging, atomic column channeling contrast imaging, and chromatic aberration-corrected energy-filtered TEM imaging will also be presented in this chapter.