'Coupled THMC' processes are an exciting area in Geo-Engineering and here uniquely collected is the latest information on developments in the numerical modelling representing the basic physics. From the GeoProc 2003 conference held in Stockholm - October 2003. This may include the effects of heat, water, mechanics and chemistry. The environmental issues around radioactive waste disposal deep in rock, for example and the search for new reserves of oil and gas are covered in detail. All contributions were carefully reviewed and edited. This is an unusually high quality collection of leading-edge information not elsewhere available in edited and coherent form.