During its 200-year history, the Philosophical Magazine was transformed from a journal that published papers on all aspects of science to one that specialised in physics and more latterly in condensed matter. From 1950 it became a journal of choice for electron microscopists and in this fourth and last volume of the series, appear classic papers by Hirsch, Whelan, Brown and Cockayne, amongst others. Also reproduced are seminal papers by Anderson, Mott, Spear and Sadoc on disordered and non-crystalline materials - work on which earned Anderson and Mott (along with van Vleck) the Nobel prize for Physics in 1977. Other important articles included are by Frank, Onsager, Pippard, Heine, Ziman, Thouless and Pepper. An interesting link with the past is a paper by Weaire and Phelan challenging Lord Kelvin's hundred-year old conjecture concerning the space-filling of cells with minimal interfacial area; Kelvin's paper was published in the journal in 1887. A comprehensive author index, with titles, for all four volumes completes the series.