Membrane Computing

This volume originated in the Workshop on Membrane Computing, WMC- CdeA 2002, which took place in Curtea de Arge¿ s, Romania, during August 19¿ 23, 2002.This was the third annual workshop held in Curtea de Arge¿s.The ?rst one, Workshop on Multiset Processing, WMP-CdeA 2000, took place in August 2000, and the proceedings were published in Lecture Notes in Computer Science, volume 2235.The second one, Workshop on Membrane Comp- ing, WMC-CdeA 2001, took place in August 2001, and selected papers were published as a special issue of Fundamenta Informaticae, volume 49, numbers 1¿3, 2002. The aim of these workshops is to provide a stimulating environment for - searchers working in the area covered by a given workshop, so that existing sci- ti?c collaborations can be strengthened, and new collaborations (and friendships) can be initiated.Indeed, all three workshops held up to now were of such ch- acter, with very international attendance and collaboration taking place across national and scienti?c boundaries.