Introduction to Information Retrieval, by Christopher D. Manning, Prabhakar Raghavan & Hinrich Schütze, Cambridge University Press, 2008. The main textbook of this course.
"Challenges on Distributed Web Retrieval," by Baeza-Yates, R.; Castillo, C.; Junqueira, F.; Plachouras, V.; Silvestri, F. Proceedings of the IEEE 23rd International Conference on Data Engineering (ICDE 2007). 15-20 April 2007 Page(s):6 - 20.
Search Engines: Information Retrieval in Practice. Bruce Croft, Donald Metzler, Trevor Strohman. Addison-Wesley, 2009. An introductory book for search engines. Recommended for undergraduate students.
Google's PageRank and Beyond: The Science of Search Engine Rankings, Amy N. Langville & Carl D. Meyer, Princeton University Press, 2006. It offers a comprehensive and erudite presentation of PageRank and related search-engine algorithms, and it is written in an approachable way, given the mathematical foundations involved.
Recommended Reading for IR Research Students. A. Moffat, J. Zobel, D. Hawking. SIGIR Forum, 39(2), 2005. Not a book, but a collection of seminal papers, more up-to-date than Sparck-Jones et al.
Information Storage and Retrieval Systems. G. Kowalski, M.T. Maybury. Springer, 2005. Takes a system approach, discussing all aspects of an Information Retrieval System.
The Geometry of Information Retrieval. C.J. van Risjbergen. Cambridge UP, 2004. An ambitious attempt to develop quantum mechanics as a new foundation for IR.
J. Zobel and A. Moffat, Inverted files for text search engines, ACM Computing Surveys, vol. 38, no. 2, 2006.
S. Melnik, S. Raghavan, B. Yang, H. Garcia-Molina, Building a distributed full-text index for the Web, ACM Transactions on Information Systems, vol. 19, no. 3, pp. 217-241, 2001.
M. W. Berry, Z. Drmac, E.R. Jessup, Matrices, vector spaces and information retrieval, SIAM Review, vol. 41, no. 2, pp. 335-362, 1999.
A. Moffat and J. Zobel, Self-indexing inverted files for fast text retrieval, ACM Transactions on Information Systems, vol. 14, no. 6, pp. 349-379, 1996.
M.W. Berry, S.T. Dumais, G.W. O'Brien, Using linear algebra for intelligent information retrieval, SIAM Review, vol. 37, no. 4, pp. 573-595, 1995.
Jon Kleinberg, Authoritative sources in a hyperlinked environment, Journal of the ACM, vol. 46, no. 5, pp. 604-632, 1999.
Sergey Brin, Larry Page, The anatomy of a large-scale hypertextual Web search engine, Computer Networks and ISDN Systems, vol. 30, no. 1-7, pp. 107-117, 1998.
Monica Bianchini, Marco Gori, Franco Scarselli, Inside PageRank, ACM Transactions on Internet Technology, vol. 5, no. 1, pp. 92-128, 2005.
Amy N. Langville and Carl D. Meyer, Deeper Inside PageRank, Internet Mathematics, vol. 1, no. 3, pp. 335-380, 2003-2004.
Pavel Berkhin, A Survey on PageRank Computing, Internet Mathematics, vol. 2, no. 1, pp. 73-120, 2005-2006.
Gravano, L., García-Molina, H., and Tomasic, A. 1999. GlOSS: text-source discovery over the Internet. ACM Trans. Database Syst. 24, 2,229-264. 1999.
Dhillon, I. S., Mallela, S., and Kumar, R. 2002. Enhanced word clustering for hierarchical text classification. In Proceedings of the Eighth ACM SIGKDD international Conference on Knowledge Discovery and Data Mining (Edmonton, Alberta, Canada, July 23 - 26, 2002).
Scholer, F., Williams, H. E., Yiannis, J., and Zobel, J. 2002. Compression of inverted indexes For fast query evaluation. In Proceedings of the 25th Annual international ACM SIGIR Conference on Research and Development in information Retrieval (Tampere, Finland, August 11 - 15, 2002).
Khan, L., Awad, M., and Thuraisingham, B. 2007. A new intrusion detection system using support vector machines and hierarchical clustering. The VLDB Journal 16, 4, 507-521, Oct. 2007.
Weikum, G. 2007. DB&IR: both sides now. In Proceedings of the 2007 ACM SIGMOD international Conference on Management of Data (Beijing, China, June 11 - 14, 2007). Extended Abstract, Slides
Search Engine Land: Must Read News about Search Marketing and Search Engines.
John Battelle's blog. John Battelle is co-founding editor of WIRED and the author of the book "The Search: How Google and Its Rivals Rewrote the Rules of Business and Transformed Our Culture."