M.A.BRAMER University of Portsmouth, UK This volume comprises the refereed technical papers presented at AI-2004, the Twenty-fourth SGAI International Conference on Innovative Techniques and Applications of Artificial Intelligence, held in Cambridge in December 2004. The conference was organised by SGAI, the British Computer Society Specialist Group on Artificial Intelligence. The papers in this volume present new and innovative developments in the field, divided into sections on AI Techniques I and II, CBR and Recommender Systems, Ontologies, Intelligent Agents and Scheduling Systems, Knowledge Discovery in Data and Spatial Reasoning and Image Recognition. This year's prize for the best refereed technical paper was won by a paper entitled Extracting Finite Structure from Infinite Language by T. McQueen, A. A. Hopgood, T. J. Allen and J. A. Tepper (School of Computing & Informatics, Nottingham Trent University, UK). SGAI gratefully acknowledges the long-term sponsorship of Hewlett-Packard Laboratories (Bristol) for this prize, which goes back to the 1980s. This is the twenty-first volume in the Research and Development series. The Application Stream papers are published as a companion volume under the title Applications and Innovations in Intelligent Systems XII. On behalf of the conference organising committee I should like to thank all those who contributed to the organisation of this year's technical programme, in particular the programme committee members, the executive programme committee and our administrators Linsay Turbert and Collette Jackson.