This is the first single-volume edition and translation of Frege's philosophical writings to include all of his seminal papers as well as substantial selections from all three of his major works. It is intended to provide the essential primary texts for students of logic, philosophical logic, philosophy of language, and philosophy of mathematics. It contains in particular Frege's four papers "Function and Concept", "On Concept and Object", "On Sense and Reference", and "Thought", and new translations of key parts of the Begriffsschrift, The Foundations of Arithmetic, and the Basic Laws of Arithmetic. The editor's substantial introduction provides the reader with an overview of the significance and development of Frege's philosophy, while the footnotes, appendices and glossary facilitate understanding of some of the more difficult elements of Frege's thought.