Statistical Language Models for Information Retrieval ChengXiang Zhai University of Illinois at Urbana Champaign Morgan & Claypool (Synthesis Lectures on Human Language Technologies, edited by Graeme Hirst), volume 1, 2008; xiii+125 pp, Princeton, NJ; paperbound, ISBN 978-1-59829-590-0, $40.00; ebook, ISBN 978-1-59829-591-7, $30.00 or by subscription