This lecture focuses, first, on archival theory and archival history in the Western world, the concepts that have animated our professional ideas, strategies, and methods, and, secondly, on archival appraisal, the process by which archivists choose a very small percentage of all human documentation for long-term or permanent preservation as archives. Archivists from the nineteenth century to the present day have gone through（or experienced, or demonstrated）four broad mental frameworks（or paradigms）in thinking about their work, their functions and activities, and their role in society. Exploring and understanding this context gives our profession a better perspective for dealing with the challenge of the digital age we now live in.