This invaluable book is a selection of papers by theoretical physicist and Nobel laureate J Robert Schrieffer. In addition to his Nobel Prize-winning work in superconductivity, Prof Schrieffer has made significant contributions to a wide variety of topics in condensed matter physics. These include the theory of soliton excitations in polyacetylene (a clear example of spin-charge separation in a condensed matter system), paramagnon theory, magnetic impurities, the physics of surfaces, high-T_c superconductivity, and the fractional quantum Hall effect.The papers are reviewed and placed in context by leading experts. The guest contributors are A Alexandrov (on electrons and phonons), T Einstein (on surfaces, ) S Kivelson (on quantum Hall effect), D Scalapino (on the BCS theory of superconductivity), F Wilczek (on solitons and fractional quantum numbers), J W Wilkins (on magnetic impurities) and S C Zhang (on high-T_c superconductivity).