To contribute to the development of a sophisticated control of bibliographic works research must build on the growing understanding of the nature of the work and the constitution of bibliographic families. The present study was designed to address the following in the context of a global bibliographic database: the OCLC Online Computer Library Center's WorldCat: the proportion of works that are members of bibliographic families; the size of each family; bibliographic characteristics that can be associated with the existence or extent of derivative bibliographic relationships; the frequency with which each type of relationship appears; and the complexity of bibliographic families. A sample of bibliographic families was constructed. Results indicate that a core of works of similar character constitute the bibliographic population of American academic and research libraries (OCLC members). It seems that the canon of derivative works is greater in the academic sphere than in the bibliographic universe represented by OCLC at large. The size of a bibliographic family seems to be related to its popularity or its canonicity. Discipline, form, and genre all fail to demonstrate any influence on derivation of works. Further study of specific segments of the bibliographic universe, for instance the literature of particular disciplines, is clearly called for. The purpose of this research is to contribute to the development of a sophisticated control of bibliographic works and families. In particular, this research is designed to build on our growing understanding of the nature of the work and the constitution of bibliographic families.