This major new study of Baudelaire is a journey into the secret language of Les Fleurs du Mal: the expressive pliabilities of its verse-forms and syntax, the fluctuations of its rhythms, its significant sonorities, its metaphorical figures and dynamic image-patterns, its network of nerves and trigger-points, its shifting underground of parallels and contrasts, analogies and antitheses. Through a strategic selection of poems constituting a 'constellation', a formal pattern of mutually illuminating parts, the analysis aims to show that form and theme are indissoluble: that each movement in the texture of the verse, each pulse, each rise and fall, each intensification or release, not only aids and abets the thrust of the poet's inspiration but is moulding and, in the end, creating the subtleties of sense, which cannot exist but in the weft and web of the breathing, evolving text. It is a study which prioritizes the individual poem, then the poem within an expanding formation of poems, then Baudelaire within and beyond that formation: an infini dans le fini. It is also an enquiry into what makes poetry, as well as a provocative contribution to the ongoing debate on the nature of criticism.