The special edition of the CSIC bulletin publishes a series of articles from the 3rd European Science Foundation (ESF) meeting of the Optimisation of Solid State Electrochemical Processes for Hydrocarbon Oxidation (OSSEP) programme which took place in Madrid on the 21st to 22nd November 2001. The workshop enjoye an excellent level of scientific contribution from the participants which further invoked fruitful and satisfying debate both within the meeting and in the accompanying social events. The theme of the meeting, "Processing of and microstructure -property relations in SOFC components and ceramic gas-separation membranes", was widely addresses from many different and stimulating angles, nineteen papers are includes in this bulletin covering the output of the workshop and encompassing the latest research efforts in the field of SOFC and gas-separation membranes from 25 labs in 11 European countries.