Introduction

Metadata is a critical component in the context of knowledge representation and data mining in digital libraries, just as it traditionally was in the context of the pre‐Web libraries. In today's digital libraries environment, in which individual collections of massive heterogeneous objects need to be unified and linked in a single resource, we are witnessing both the growth of different metadata and the attempts to reconcile the common attributes in the existing overlapping standards. The goal is to access relevant information seamlessly, regardless of its type (e.g., visual and museum objects, historical data, cultural heritage, scientific data), location, and scholarly tradition (e.g., librarians, archivists, scientists). This special issue of JASIS addresses different applications of metadata standards in geospatial collections, education, historical costume collection, data management, and information retrieval, and explores the future thinking of metadata standards for digital libraries.