Finding information in books: characteristics of full-text searches in a collection of 10 million books

Searching large collections of digitized books is a relatively new area in information-seeking and retrieval research, made possible by initiatives such as Google Books and the HathiTrust Digital Library. The availability of large full-text book collections is transforming how users search and interact with information in books, but the characteristics of these changes are unknown. This paper aims to provide insight into the characteristics of full-text searches in a large collection of digitized books and is the first step in a broader research agenda intended to improve book retrieval. To better understand the types of queries that users are issuing to full-text-book collections, we analyzed a full year of anonymized query logs from the HathiTrust Digital Library full-text search engine. We also manually classified a random sample of 600 queries to develop a taxonomy of book search query types. We found that users are beginning to search for information in books instead of searching for books. Searches still largely follow bibliographic models, but, as expected, new types of searches are beginning to take advantage of full-text capabilities. Additionally, comparing the results of our query log analysis to searches in other domains, we found similar search patterns including short queries, sessions with only a few queries, and users viewing only a few pages of results per query. We discuss how these findings can be used to characterize users of large full-text book collections.