This book constitutes the refereed proceedings of the 17th and 18th International Conference on Formal Grammar 2012 and 2013, collocated with the European Summer School in Logic, Language and Information in August 2012/2013. The 18 revised full papers were carefully reviewed and selected from a total of 27 submissions. The focus of papers are as follows: formal and computational phonology, morphology, syntax, semantics and pragmatics; model-theoretic and proof-theoretic methods in linguistics; logical aspects of linguistic structure; constraint-based and resource-sensitive approaches to grammar; learnability of formal grammar; integration of shastic and symbolic models of grammar; foundational, methodological and architectural issues in grammar and linguistics, and mathematical foundations of statistical approaches to linguistic analysis.