Delivered over the past two decades at the International School of Subnuclear Physics in Erice, Sicily, this collection of review articles on topics in theoretical high energy physics is the result of the organization of material scattered throughout the literature until then.Delivered over the past two decades at the International School of Subnuclear Physics in Erice, Sicily, this collection of review articles on topics in theoretical high energy physics is the result of the organization of material scattered throughout the literature until then.This collection of review lectures on topics in theoretical high energy physics has few rivals for clarity of exposition and depth of insight. Delivered over the past two decades at the International School of Subnuclear Physics in Erice, Sicily, the lectures help to organize and explain material that a the time existed in a confused state, scattered in the literature. At the time they were given they spread new ideas throughout the physics community and proved very popular as introductions to topics at the frontiers of research.Preface; Acknowledgements; 1. An introduction to unitary symmetry; 2. Soft pions; 3. Dilatations; 4. Renormalization and symmetry: a review for non-specialists; 5. Secret symmetry: an introduction to spontaneous symmetry breakdown and gauge fields; 6. Classical lumps and their quantum descendants; 7. The uses of instantous; 8. 1/N; Appendices; Notes and references. ...must surely be an invaluable supplement and resource for any advanced course in particle physics...[Coleman's] writing is elegant, lean, utterly authoritative--and a bit sly and tricky...this book is a classic. Physics Today