This paper studies the challenge of representing aggregate works such as encyclopaedia, collected poems and journals in digital
libraries. Reflecting on materials used by humanities academics, it demonstrates the complex range of aggregate types and
the problems of representing this heterogeneity in the digital library interface. We demonstrate that aggregates are complex
and pervasive, challenge many common assumptions and confuse the boundaries between organisational levels within the library.
The challenge is amplified by concrete examples.
Keywords Digital Libraries - Architecture - Collection Building