The genesis of this volume was the participation of the editors in an ACMlSIGIR (Association for Computing Machinery/Special Interest Group on Information Retrieval) workshop entitled "Beyond Word Relations" (Hetzler, 1997). This workshop examined a number of relationship types with significance for information retrieval beyond the conventional topic-matching relationship. From this shared participation came the idea for an edited volume on relationships, with chapters to be solicited from researchers and practitioners throughout the world. Ultimately, one volume became two volumes. The first...