The importance of open source systems in the context of libraries and archives is perhaps greater now than ever before. This book explains the essentials of open source systems to benefit academic and public librarians and archivists who have a vested interest in the future of integrated online library systems. Author Christinger Tomer, who has studied open source systems for more than two decades and used them extensively in both teaching and consulting, provides brief histories of both library automation and open source software, in the latter instance focusing on aspects that have more directly influenced library and archival computing. He then describes and analyzes key open source systems and critically compares them to commercial systems in terms of design, functionality, and ease of administration. The book concludes with an in-depth description of how these systems are currently being employed as well as insightful predictions about how this segment of the software environment is likely to evolve.