Graph-structured databases are widely prevalent, and the problem of effective search and retrieval from such graphs has been receiving much attention recently. For example, the Web can be naturally viewed as a graph. Likewise, a relational database can be viewed as a graph where tuples are modeled as vertices connected via foreign-key relationships. Keyword search querying has emerged as one of the most effective paradigms for information discovery, especially over HTML documents in the World Wide Web. One of the key advantages of keyword search querying is its simplicity – users do not have to learn a complex query language, and can issue queries without any prior knowledge about the structure of the underlying data. This book presents techniques for user-friendly, high quality and efficient searching of graph structured databases. The methods and techniques presented should help shed some light on this new and exciting field, and should especially be useful to professionals in Computer science or Information technology fields, or anyone else who may be considering a research career in the area of Databases and Information Retrieval.