Interpretation of the new information arising from the Plas-modium falciparum Genome Project requires a good working knowledge of the ultrastructure of the parasite; however manyaspects of the morphology of this species remain obscure.Lawrence Bannister, John Hopkins and colleagues here give an illustrated overview of the three-dimensional (3-D) organiz-ation of the merozoite, ring, trophozoite and schizont stages ofthe parasite, based on available data that include 3-D reconstruction from serial electron microscope sections. The review de-scribes the chief organelles present in these stages, emphasizingthe continuity of structure in addition to specialized, stage-spe-cific features developed during the asexual erythrocytic cycle