This document discusses principles of external fixation for fractures. It describes two basic types of external fixators - pin fixators and ring fixators. Pin fixators can be configured unilaterally or bilaterally in one or two planes. Ring fixators consist of complete or partial rings connected by rods. The document also discusses hybrid external fixation combining wires and pins, general methods for application of half pins and wires, factors affecting fixator stiffness, and techniques to promote fracture healing like dynamization.