We present a characterization of the core entities and relationships of the Functional Requirements for Bibliographic Records (FRBR) in first order logic. Evidence from the text and diagrams in FRBR support the identification of axioms that capture the constraints and assumptions built into the model. The result is an axiomatic system that clarifies the meaning of the specification. This approach provides a more systematic way of clarifying ambiguities and confusions in the interpretation of FRBR than separate analyses of individual problems and allows scholars and system builders concerned with bibliographic theory to clarify their interpretation of the specification prior to the choice of an implementation language, such as RDF or OWL.