The volume begins with a rationale for multilevel modeling (MLM). Different aspects of MLM such as centering and modeling error terms are discussed, and examining hypotheses within the multilevel framework is considered in detail. Step by step instructions for conducting multilevel analyses using the program HLM are presented, and these instructions are linked to data sets and program files on a website. "The SAGE Library in Social and Personality Psychology Methods" provides students and researchers with an understanding of the methods and techniques essential to conducting cutting-edge research. Each volume within the Library explains a specific topic and has been written by an active scholar (or scholars) with expertise in that particular methodological domain. Assuming no prior knowledge of the topic, the volumes are clear and accessible for all readers. In each volume, a topic is introduced, applications are discussed, and readers are led step by step through worked examples. In addition, advice about how to interpret and prepare results for publication are presented.