In this volume we present the contributions for the 18th European Conference on Genetic Programming (EuroGP 2005). The conference took place from 30 March to 1 April in Lausanne, Switzerland. EuroGP is a well-established conf- ence and the only one exclusively devoted to genetic programming. All previous proceedings were published by Springer in the LNCS series. From the outset, EuroGP has been co-located with the EvoWorkshops focusing on applications of evolutionary computation. Since 2004, EvoCOP, the conference on evolutionary combinatorial optimization, has also been co-located with EuroGP, making this year's combined events one of the largest dedicated to evolutionary computation in Europe. Genetic programming (GP) is evolutionary computation that solves complex problems or tasks by evolving and adapting a population of computer programs, using Darwinian evolution and Mendelian genetics as its sources of inspiration. Some of the 34 papers included in these proceedings address foundational and theoretical issues and there is also a wide variety of papers dealing with di?erent application areas, such as computer science, engineering, language processing, biology and computational design, demonstrating that GP is a powerful and practical problem-solving paradigm.

In this volume we present the accepted contributions for the 7th European C- ference on Genetic Programming (EuroGP 2004). The conference took place on 5 7 April 2004 in Portugal at the University of Coimbra, in the Department of Mathematics in Pra, ca Dom Dinis, located on the hill above the old town. EuroGP is a well-established conference and the sole one exclusively de- ted to Genetic Programming. Previous proceedings have all been published by Springer-Verlag in the LNCS series. EuroGP began as an international wor- hop in Paris, France in 1998 (14 15 April, LNCS 1391). Subsequently the wor- hop was held in G] oteborg, Sweden in 1999 (26 27 May, LNCS 1598) and then EuroGP became an annual conference: in 2000 in Edinburgh, UK (15 16 April, LNCS 1802), in 2001 at Lake Como, Italy (18 19 April, LNCS 2038), in 2002 in Kinsale, Ireland (3 5 April, LNCS 2278), and in 2003 in Colchester, UK (14 16 April, LNCS 2610). From the outset, there have always been specialized wor- hops, co-located with EuroGP, focusing on applications of evolutionary al- rithms (LNCS 1468, 1596, 1803, 2037, 2279, and 2611). This year the EvoCOP workshop on combinatorial optimization transformed itself into a conference in its own right, and the two conferences, together with the EvoWorkshops, EvoBIO, EvoIASP, EvoMUSART, EvoSTOC, EvoHOT, and EvoCOMNET, now form one of the largest events dedicated to Evolutionary Computation in Europe."

This book constitutes the refereed proceedings of the 6th European Conference on Genetic Programming, EuroGP 2003, held in Essex, UK in April 2003. The 45 revised papers presented were carefully reviewed and selected from 61 submissions. All current aspects of genetic programming and genetic algorithms are addressed, ranging from foundational, theoretical, and methodological issues to advanced applications in various fields.