The Dewey Decimal Classification (DDC) is structured around ten main classes covering the entire world of knowledge; each main class is further structured into ten hierarchical divisions, each having ten sections of increasing specificity.[1] As a system of library classification the DDC is "arranged by discipline, not subject", so a topic like clothing is classed based on its disciplinary treatment (psychological influence of clothing at 155.95, customs associated with clothing at 391, and fashion design of clothing at 746.92) within the conceptual framework.[2] The list below presents the ten main classes, hundred divisions, and thousand sections.[3]