The Physics Companion, Volume I: The Newtonian Perspective is a companion to introductory mechanics for high school students and anyone interested in self-study. Volume I builds the foundation for describing our universe. Across eight units it covers the essential skills of measurement and problem solving, motion in one and two dimensions, Newton's laws and dynamics, and the conservation of energy and momentum. Every topic pairs clear explanations with worked examples, labeled diagrams, guiding questions, and practice problems with full step-by-step solutions. Key equations, a complete glossary, and a detailed index are built in, so students can review efficiently.