In the development of documentation studies at the University of Tromsø and the founding of the Document Academy it was asserted that one should view a document as having three complementary and simultaneous aspects: physical, mental, and social. These three document dimensions and relationships between them are discussed. Physicality is a necessary but not a sufficient condition for being a document, there must also be a mental angle, which, in turn, entails a social (cultural) angle. The physical disposition of documents is influenced by social controls. The inability of any one angle to fully characterize a document explains the role of documents in the social construction of reality and why “relevance” in retrieval evaluation can be understood but resists scientific treatment.