Advanced tomography techniques for materials applications. Three-dimensional (3D) tomography using electrons and x-rays has pushed and expanded our understanding of the micro- and nanoscale spatial organization in inorganic, organic, and biological materials. While significant impact on the field of materials science has already been realized from tomography applications, new advanced methods are quickly expanding the versatility of this approach. This issue of MRS Bulletin describes some of these latest developments in analytical electron tomography. The cover shows cryo-scanning transmission electron tomography of mammalian fibroblasts. Because of the quantitative contrast formation, dense areas are seen as bright in volume representation, with sparse areas seen as transparent. Image courtesy of Wiley. (E.F. Pettersen, T.D. Goddard, C.C. Huang, G.S. Couch, D.M. Greenblatt, E.C. Meng, T.E. Ferrin, J. Comput. Chem.25 [13], 1605 [2004]). See the technical theme that begins on page 516.