This book constitutes the thoroughly refereed post-proceedings of the 9th Workshop on the Foundations of Genetic Algorithms, FOGA 2007, held in Mexico City, Mexico in January 2007.The 11 revised full papers presented were carefully reviewed and selected during two rounds of reviewing and improvement from 22 submissions. The papers address all current topics in the field of theoretical evolutionary computation including evolution strategies, evolutionary programming, and genetic programming, and also depict the continuing growth in interactions with other fields such as mathematics, physics, and biology. Readers will find here a fascinating text that is the thoroughly refereed post-proceedings of the 9th Workshop on the Foundations of Genetic Algorithms, FOGA 2007, held in Mexico City in January 2007. The 11 revised full papers presented were carefully reviewed and selected during two rounds of reviewing and improvement from 22 submissions. The papers address all current topics in the field of theoretical evolutionary computation and also depict the continuing growth in interactions with other fields such as mathematics, physics, and biology Inbreeding Properties of Geometric Crossover and Non-geometric Recombinations 1(14) Alberto Moraglio Riccardo Poli Just What Are Building Blocks? 15(20) Christopher R. Stephens Jorge Cervantes Sufficient Conditions for Coarse-Graining Evolutionary Dynamics 35(19) Keki Burjorjee On the Brittleness of Evolutionary Algorithms 54(16) Thomas Jansen Mutative Self-adaptation on the Sharp and Parabolic Ridge 70(27) Silja Meyer-Nieberg Hans-Georg Beyer Genericity of the Fixed Point Set for the Infinite Population Genetic Algorithm 97(13) Tomas Gedeon Christina Hayes Richard Swanson Neighborhood Graphs and Symmetric Genetic Operators 110(13) Jonathan E. Rowe Michael D. Vose Alden H. Wright Decomposition of Fitness Functions in Random Heuristic Search 123(15) Yossi Borenstein Riccardo Poli On the Effects of Bit-Wise Neutrality on Fitness Distance Correlation, Phenotypic Mutation Rates and Problem Hardness 138(27) Riccardo Poli Edgar Galvan-Lopez Continuous Optimisation Theory Made Easy? Finite-Element Models of Evolutionary Strategies, Genetic Algorithms and Particle Swarm Optimizers 165(29) Riccardo Poli William B. Langdon Maurice Clerc Christopher R. Stephens Saddles and Barrier in Landscapes of Generalized Search Operators 194(19) Christoph Flamm Ivo L. Hofacker Barbel M.R. Stadler Peter F. Stadler Author Index 213