Complex systems and their phenomena are ubiquitous as they can befound in biology, finance, the humanities, management sciences,medicine, physics and similar fields. For many problems in these fields, there are no conventional ways tomathematically or analytically solve them completely at low cost. Onthe other hand, nature already solved many optimization problemsefficiently. Computational intelligence attempts to mimicnature-inspired problem-solving strategies and methods. These strategies can be used to study, model and analyze complexsystems such that it becomes feasible to handle them. Key areas ofcomputational intelligence are artificial neural networks,evolutionary computation and fuzzy systems. As only a few researchers in that field, Rudolf Kruse has contributedin many important ways to the understanding, modeling and applicationof computational intelligence methods. On occasion of his 60thbirthday, a collection of original papers of leading researchers inthe field of computational intelligence has been collected in thisvolume.