ABSTRACT The present paper covers the results of different transmission electron microscopy studies on silver halide microcrystals. Pure AgBr as well as core-shell AgBr-AgBrI crystals are investigated. In the former parallel and non-parallel twinning modes yielding tabular and needle- or tetrahedral-shaped microcrystals, respectively, are discussed. Also the short-range-order of Ag+ interstitials around the twin planes as determined from diffuse intensity in reciprocal space is described. The latter yields a technique to determine the variant in which dislocations are located in certain core-shell microcrystals. The introduction of iodine also results in the presence of inclined stacking faults in the shell and of long-range iodine ordering on the crystal surface.