The passage you provided outlines the classification guidelines for natural and applied sciences according to the Dewey Decimal Classification (DDC) system: Natural sciences: These are sciences that deal with matter, energy, or natural processes, and they are classified under the 500s in the DDC. Interdisciplinary works: These works that cover both natural and applied sciences should also be classified under the 500s. Natural history: Works on natural history are classified under 508. Scientific principles: When dealing with scientific principles related to a subject, these should be classified with the subject itself, plus a notation from Table 1. For example, the scientific principles of photography would be classified as 770.1. Government policy on science: This is classified under 338.9. Applied sciences: These are classified under the 600s.