Part 1 of this series described how focused ion beam (FIB) microsurgery is used to successfully cross-section and prepare materialspecific samples for SEM and TEM analysis. In Part 2, we detailed how FIB is also the tool of choice to prepare site-specific samples, particularly for transmission electron microscopy (TEM) analysis. In this final article of this series, we describe actual sample preparation, cutting a selected area la size and mounting it on a grid for FIB preparation. Focused ion beams are very useful in preparing TEM specimens that have unique characteristics. In particular, the ability of such systems to image submicron features within a structure has allowed accurate identification of the precise place to make a membrane.