Objectives: This study characterizes the nature, size, and knowledge gaps of the public health emergency preparedness (PHEP) literature. Methods: Systematic review of PHEP articles published in 10 relevant journals from 2000 through 2008 was conducted. An inclusion process and coding sheet was developed; articles were coded on the basis of content for variables, including type of methods used, disaster type, disaster life cycle focus, and article focal point. Descriptive analyses and cross-tabulations were used to characterize the nature of the literature. Results: The sample included 823 articles; human-made disasters (39.4%, n = 323) were the most common, followed by natural disasters (30.7%, n = 252). The preparedness life cycle phase represented 60.5% (n = 497) of articles. Overall, 67.8% (n = 558) of articles were nonempirical; however, this differed by disaster type and focal point. Discussion: Most of the PHEP literature is based on commentaries and other nonempirical articles forcing policymakers and practitioners to rely on weak anecdotal evidence or opinions for decision making. Several literature gaps are identified and presented as areas for future research. More research utilizing diverse methods and data sets is needed to build a strong evidence-based knowledge base on many PHEP topics. Copyright © 2010 Wolters Kluwer Health.