This book describes the fundamentals of Jacy, an implementation of a Japanese head-driven phrase structure grammar with many useful linguistic implications. Jacy presents sound information about the Japanese language (syntax, semantics, and pragmatics) based on implementation and tested on large quantities of data. As the grammar development was done in a multilingual environment, Jacy also showcases both multilingual concepts and differences among the languages and demonstrates the usefulness of semantic analysis in language technology applications.