Baudelaire's "La Vie antérieure" is built on a single extended metaphor of the soul's pre-existence in a marine paradise: "J'ai longtemps habité sous de vastes portiques / Que les soleils marins teignaient de mille feux," the metaphor creating a vision of memory that is simultaneously physical and spiritual; Rimbaud's "Le Bateau ivre" sustains its central metaphor of the poet as a runaway boat throughout sixty stanzas, using the vehicle's specificity, the sea's currents, the boat's planks, its rudder, to explore the psychology of visionary liberation with concrete physical detail; Proust's analysis of metaphor in Le Temps retrouvé, though in prose, provides the most searching account of what metaphor achieves: by identifying two different things, it creates a form of knowledge that neither concept could achieve alone, extracting the essence common to two experiences; A student learning to write métaphores should begin with the vehicle rather than the tenor: instead of deciding what to say about grief and then finding an image for it, find an image that captures some essential quality and then discover what it knows about grief; Hugo's "Booz endormi" builds its visionary metaphor of the night sky: "Ruth songeait et Booz dormait; l'herbe était noire; / Les grelots du troupeau palpitaient vaguement" creating a metaphoric fusion of the human and natural worlds that achieves the mystical quality of biblical vision; The test of a great metaphor is whether it creates genuine insight: not just a decorative comparison but a revelation that the two things identified share something essential that changes how we understand both of them.