The outstanding merits of scanning transmission electron tomography as a technique for the investigation of the intal structure and morphology of nanoparticle and nanocluster materials are summarized with the aid of numerous typical illustrations. Reference is made also to the significant advances that have arisen in probing ultrastructural characteristics of nanoscale solids using aberration-corrected (AC) electron microscopy (EM). Information of a unique kind may be retrieved by combining the imaging and analytical power of ACEM.