This new book offers a comprehensive and accessible introduction to Frege's remarkable philosophical work, examining the main areas of his writings and demonstrating the connections between them. Frege's main contribution to philosophy spans philosophical logic, the theory of meaning, mathematical logic and the philosophy of mathematics. The book clearly explains and assesses Frege's work in these areas, systematically examining his major concepts, and revealing the links between them. The emphasis is on Frege's highly influential work in philosophical logic and the theory of meaning, including the features of his logic, his conceptions of object, concept and function, and his seminal distinction between sense and reference. Frege will be invaluable for students of the philosophy of language, philosophical logic, and analytic philosophy.