Summary of: Preface. Invited Papers. Theory of the luminescence of porous silicon (C. Delerue, M. Lannoo, G. Allan). Spectroscopic identification of the luminescence mechanism of highly porous silicon (P.D.J. Calcott et al.). The luminescence of porous Si: the case for the surface state mechanism (F. Koch, V. Petrova-Koch, T. Muschik). Photoluminescence and electroluminescence from electrochemically oxidized porous silicon layers (F. Muller et al.). Electrical properties of luminescent porous silicon (H. Koyama, N. Koshida). Defect and structure analysis of n+-, p+- and p-type porous silicon by the electron paramagnetic resonance technique (H.J. van Bardeleben et al.). Low-energy scanning cathodoluminescence spectroscopy and microscopy of porous silicon layers (M. Gu et al.). Luminescence and optical properties of siloxene (M. Stutzmann et al.). Aging phenomena of light emitting porous silicon (T. Ito, A. Hiraki). Porous silicon electroluminescent devices (W. Lang, P. Steiner, F. Kozlowski). Author index. Subject index. Materials index.