A collection of papers dealing with combinatorics on words, codes, semigroups, automata, languages, molecular computing, transducers and logics, related to the impressive work of Gabriel Thierrin. This volume is in honour of Professor Thierrin on the occasion of his 80th birthday.

Some operators on families of fuzzy languages and their monoids, P.R.J. Asveld; liars, demons, and chaos, C.S. Calude et al; conditional grammars with restrictions by syntactic parameters, J. Dassow; circularity and other invariants of gene assembly in ciliates, A. Ehrenfeucht et al; catenation closed pairs and forest languages, C-M Fan and H-J Shyr; valence grammars with target sets, H. Fernau and R. Stiebe; minimal recognizers and syntactic monoids of DR tree languages, F. Gecseg and M. Steinby; visualizing languages using primitive powers, T. Head; disjunctivity, H. Jurgensen; string operations suggested by DNA biochemistry - the balanced cut operation, L. Kari and A. Pun; how to generate binary codes using context-free grammars, L. Kaszonyi; generation and parsing of morphism languages by uniquely parallel parsable grammars, J. Lee and K. Morita; on the generative power of iterated transductions, V. Manca; words, dyck paths, trees, and bijections, H. Prodinger; iterated morphisms with complementarity on the DNA alphabet, A. Salomaa; topologies for the set of disjunctive w-words, L. Staiger; and other papers.