The Institute of Physics Conference Series is a leading International medium for the rapid publication of proceedings of major conferences and symposia reviewing new developments in physics and related areas. Volumes in the series comprise original refereed papers and are regarded as standard referee works. As such, they are an essential part of major libration collections worldwide.The twelfth conference on the Microscopy of Semiconducting Materials (MSM) was held at the University of Oxford, 25-29 March 2001. MSM conferences focus on recent international advances in semiconductor studies carried out by all forms of microscopy. The event was organized with scientific sponsorship by the Royal Microscopical Society, The Electron Microscopy and Analysis Group of the Institute of Physics and the Materials Research Society. With the continual shrinking of electronic device dimensions and accompanying enhancement in device performance, the understanding of semiconductor microscopic properties at the nanoscale (and even at the atomic scale) is increasingly critical for further progress to be achieved. This conference proceedings provides an overview of the latest instrumentation, analysis techniques and state-of-the-art advances in semiconducting materials science for solid state physicists, chemists, and materials scientists.