This is the first single-volume edition and translation of Frege's philosophical writings to include 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, metaphysics and the philosophy of language. It contains in particular Frege's four essays "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. Additional selections have been made from his Collected Papers, Posthumous Writings and Correspondence. 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.