Hypercomplex Analysis and Applications : [this volume contains some papers written by the participants to the Session Clifford and Quaternionic Analysisʺ of the 7th ISAAC Conference (hosted at the Imperial College London UK July 2009)] The purpose of the volume is to bring forward recent trends of research in hypercomplex analysis. The list of contributors includes first rate mathematicians and young researchers working on several different aspects in quaternionic and Clifford analysis. Besides original research papers there are papers providing the state of the art of a specific topic sometimes containing interdisciplinary fields. The intended audience includes researchers PhD students postgraduate students who are interested in the field and in possible connection between hypercomplex analysis and other disciplines including mathematical analysis mathematical physics algebra.