Sidney Coleman (1937–2007) earned his doctorate at Caltech under Murray Gell-Mann.Before completing his thesis, he was hired by Harvard and remained there his entire career.A celebrated particle theorist, he is perhaps best known for his brilliant lectures, given at Harvard and in a series of summer school courses at Erice, Sicily.Three times in the 1960s he taught a graduate course on Special and General Relativity; this book is based on lecture notes taken by three of his students and compiled by the Editors.