Principles of Economics[1] is a leading political economy or economics textbook of Alfred Marshall (1842–1924), first published in 1890.[2] It was the standard text for generations of economics students. Called his magnum opus,[3] it ran to eight editions by 1920.[4] A ninth (variorum) edition was published in 1961, edited in 2 volumes by C. W. Guillebaud.[5]

Marshall began writing the Principles of Economics in 1881 and he spent much of the next decade at work on the treatise. His plan for the work gradually extended to a two-volume compilation on the whole of economic thought; the first volume was published in 1890 to worldwide acclaim that established him as one of the leading economists of his time. The second volume, which was to address foreign trade, money, trade fluctuations, taxation, and collectivism, was never published at all. Over the next two decades he worked to complete his second volume of the Principles, but his unyielding attention to detail and ambition for completeness prevented him from mastering the work’s breadth.