This report is the second of three volumes describing a multi-year research program to develop and evaluate web based training in critical thinking for Army officers. The first volume presents an overview of the research effort that developed and validated a theoretical model for the training, selected and validated eight high impact critical thinking skills for Army officers, and developed and evaluated the training course. This volume describes the results of a literature review on critical thinking, a model of critical thinking that forms the theoretical basis for the training, and investigations that were conducted to validate the model. Volume Three describes a web-based prototype training system that trains two critical thinking skills. Included in Volume Three are a description of the functional requirements, pedagogical principles, course content, and evaluation of the training. A fourth report (Fischer, Spiker, & Riedel, 2008) describes an expanded version of the training system that provides training for eight critical thinking skills for Army officers.