Back-of-the-book indexes are traditional devices that help readers to get access to document content. Such indexes present the book topics in a different form and order than in the document itself. In this paper, we show that back-of-the-book indexes, which give a synthetic view over the document content, are quite similar to indicative summaries. The new methods that are developed for the fine-grained indexing of documents can be compared with summarization technics. Besides their similarities, both types of tools belong to different traditions and the underlying methods are quite different. The confrontation helps to understand the specificity of each approach.
