Tools for Modeling Systems introduces The Language of Patterns as a path to systems analysis and modeling. The Language of Patterns is a descriptive modeling language used at each step of the scientific knowledge construction process or Progression of Inquiry. Using these fundamental ideas, the Language of Patterns develops the tools for critical thinking and analysis that underlie all knowledge construction. The Language of Patterns is used to characterize, explore, and understand any system of interest. Scientific inquiry uses the Language of Patterns at every level from observation, through to model building, hypothesis testing, and experimental verification. Critical thinking skills and the process of scientific inquiry are practiced anytime the Language of Patterns is used. This simple text and practice workbook introduces the fundamentals of systems analysis, scientific thinking and critical analysis in a non-technical and easily accessible method. It includes a coherent series of graphical analyzers to guide learning and analysis.