This book investigates memory-based syntactic parsing§of natural language, using an agent-based,§evolutionary computing approach. The proposed§technique, dubbed GRAEL (GRAmmar EvoLution), offers a§general purpose method for processing syntactically§annotated corpora of natural language. It attempts to§improve grammars by grounding the evolutionary§optimization of syntactic structures in agent-based§communication attempts. Using the same architecture,§but different information sources, GRAEL can be shown§to successfully handle a diverse range of grammar§engineering tasks, such as grammar optimization§(redistributing the probability mass of a§corpus-induced grammar) and grammar rule discovery§(automatically adding useful new rules to an existing§ grammar). This book also describes how GRAEL can be§used to induce grammars for natural language from§scratch (grammar induction) and offers insights§into the origins of syntactic patterns in human language.