The automatic generation of back-of-the book indexes seems to be out of sight of the Information Retrieval and Natural Language Processing communities, although the increasingly large number of books available in electronic format, as well as recent advances in keyphrase extraction, should motivate an increased interest in this topic. In this paper, we describe the background relevant to the process of creating back-of-the-book indexes, namely (1) a short overview of the origin and structure of back-of-the-book indexes, and (2) the correspondence that can be established between techniques for automatic index construction and keyphrase extraction. Since the development of any automatic system requires in the first place an evaluation testbed, we describe our work in building a gold standard collection of books and indexes, and we present several metrics that can be used for the evaluation of automatically generated indexes against the gold standard. Finally, we investigate the propertie...