"Version: 20240501"--Title page verso.Includes bibliographical references.1. Introduction -- 1.1. Prelude2. Invitation to integrable quantum field theories -- 2.1. Classical integrability -- 2.2. Exact S-matrices3. The sine-Gordon model -- 3.1. A very special theory -- 3.2. Classical aspects -- 3.3. Quantum aspects -- 3.4. Breather S-matrix, mixed S-matrix -- 3.5. Sine-Gordon and the XXZ spin-c…