This document summarizes a research paper that presents a semantic importing approach called Package-based Description Logics (P-DL) for knowledge reuse from multiple ontologies. P-DL allows ontologies (called packages) to selectively reuse subsets of definitions from other packages while preserving context and unsatisfiability. It supports transitive knowledge reuse through compositionally consistent domain relations between packages. The paper outlines P-DL's syntax, semantics and modeling abilities and compares it to existing modular ontology languages.