This chapter outline from Outdoor Emergency Care: A Patroller’s Guide to Medical Care focuses on the critical medical condition of shock, defined as inadequate blood flow leading to cellular hypoxia. The text details the causes of shock, categorizing them into pump failure, blood vessel failure, and low fluid volume. It further explains the body's compensatory mechanisms and the progression through compensated and decompensated stages. The outline also describes four major types of shock: hypovolemic, cardiogenic, distributive (including anaphylactic, septic, and neurogenic), and obstructive, along with their specific characteristics and management principles, concluding with the signs, symptoms, and initial treatment of shock.