A recent survey of conceptual clustering:

Fisher, D. (2002). "Conceptual Clustering," in W. Klosgen and J. Zytkow (eds.), Handbook of Data Mining and Knowledge Discovery, Oxford University Press, 388--396, Chapter 16.5.2. preprint

My latest installment in the Cobweb family of systems introduced a novel form of interative optimization that redistributed many objects simultaneously within a clustering by taking advantage of a clustering's hierarchical organization. I call the strategy hierarchical redistribution, and it was inspired by incremental clustering operations of merging and by macro learning in problem-solving work and is a good scaleup strategy for data mining:

Fisher, D. (1995). "Optimization and Simplification of Hierarchical Clusterings," First International Conference on Knowledge Discovery in Databases, Montreal, Canada: AAAI Press, 118--123.

Fisher, D. (1996). "Iterative Optimization and Simplification of Hierarchical Clusterings," Journal of Artificial Intelligence Research, 4, 147--179.

Older, but inflential surveys are:

Fisher, D., & Langley, P. (1986). "Methods of conceptual clustering and their relation to numerical taxonomy," in W. Gale (ed.), Artificial Intelligence and Statistics. Addison-Wesley, 77--116.

Fisher, D., & Langley, P. (1985). "Approaches to Conceptual Clustering," Proceedings of the International Joint Conference on Artificial Intelligence, Los Angeles, CA: Morgan Kaufmann, 691--697.

This was my initial idea for a dissertation

Fisher, D. (1985). "A Proposed Method of Conceptual Clustering for Structured and Decomposable Objects," in the Proceedings of the Third International Machine Learning Workshop, Skytop, PA, 38--40.