Marshall’s fondness for metaphors and analogies is often taken as a sign of weakness, a means to hide lack of analytical rigour or even contradiction. In 1930, Sraffa’s sarcastic comments on Robertson’s profusion of metaphors contributed to the dismissal of Marshall’s research programme. More recently, his biological analogies were played down by some interpreters (Mirowski, Thomas), but re-evaluated by others (Niman, Foss, Levine). Black’s 1962 seminal article acknowledged the cognitive content of metaphors, opening the way to a thorough reconsideration of their role in the growth of science (Hesse, Boyd, Ricouer, Holton). Starting from this new perspective, the paper places Marshall’s metaphors and analogies in historical context and examines in detail the three main sets of metaphorical reasoning which helped him convey his views on method: 1) the representation of science as machinery of thought, similar to material machinery; 2) the role of strategy and tactics in the study of economic history; 3) the relationship between biological and mechanical analogies in economics. All the three types of metaphorical thought, though with different accent, stress the need to discover patterns of repetition amidst social change. This general idea, stemming from Marshall’s conception of piecemeal, localised evolution, forms the core of his method and runs through his economics, from partial equilibrium to industrial analysis.