This book outlines and evaluates the digital reference services in libraries worldwide. The work is based on an international collaborative project between two groups from German and Chinese institutions, during which digital reference services provided by nearly 200 libraries all over the world were evaluated. The book also examines the reasons for the resulting differences; it also contains more generic proposals and perspectives on digital reference services. - An international, evaluative approach is taken - Includes unique information - which has never before being gathered and evaluated - Includes a brief introduction to the basic knowledge and development in the field of digital reference service in the library