In the digital library context, the role of metadata has become more important than ever before, because the effective organization of networked information clearly depends on the effective management and organization of metadata. The issue of metadata has been approached variously by different intellectual communities. The two main approaches may be characterized as: (1) the library science oriented bibliographic control approach; and (2) the computer science oriented data management approach. This paper examines the different concepts and orientations of the two major approaches contributing to the metadata discussion, and proposes an integrated concept of metadata to facilitate the merging of these two approaches. This paper also discusses the on-going efforts to establish metadata standards, and compares different metadata formats.