Book excerpt: The symposium entitled "New Developments in Porous Silicon. Relation with Other Nanostructured Porous Materials" took place in Strasbourg on 4-7 June 1996 hosted by the EMRS Society. Its objectives were to assess the recent developments in porous silicon research and make the 'porous Si community' more aware of related porous materials. The 71 papers contained in these proceedings account for about 80% of the work presented at the meeting and cover nine different topic areas. Chapter 1 focuses on some recent advances in porous Si fabrication and a new formation mechanism involving specific point defects, extensions to the basic anodization process for preparing macropore arrays, multilayers as well as both thin and thick high porosity layers and the realisation of luminescent porous structures from device quality &agr;-Si:H material. Controlled chemical modification of the internal surface of porous Si, an important emerging technique for both stabilising, understanding and introducing new functionality into the properties of the material is discussed in chapter 2 along with the new and exciting developments taking place in the nanocomposites area. The papers in chapter 3 discuss photochemical effects, properties of 'wet' and 'dry' porous Si layers and new approaches to characterising 'wet' material along with an important highlight of the symposium - blue emission in oxide-free layers. Chapter 4 covers many new developments and the refining of existing techniques regarding characterising porous Si and chapter 5 reviews the luminescent silicon nanostructures that have been fabricated other than anodization. The presentation of various porous materials and overviews on the fabrication characterisation and applications of porous alumina are covered in chapter 6, and chapter 7 focuses on the growing interest in porous Si multilayer structures and the potential for realising practical SiLEDs with chapter 8 covering the work that has been presented in this field. New applications for porous Si materials which has an enormous world-wide interest is discussed in the final chapter of the proceedings.