Who among us has not dreamt, in moments of ambition, of the miracle of a poetic prose, musical without rhythm and rhyme, supple and staccato enough to adapt to the lyrical stirrings of the soul, the undulations of dreams, and sudden leaps of consciousness. This obsessive idea is above all a child of giant cities, of the intersecting of their myriad relations.— Dedication of Le Spleen de Paris
Baudelaire is one of the major innovators in French literature. His poetry is influenced by the French romantic poets of the earlier 19th century, although its attention to the formal features of verse connects it more closely to the work of the contemporary "Parnassians". As for theme and tone, in his works we see the rejection of the belief in the supremacy of nature and the fundamental goodness of man as typically espoused by the romantics and expressed by them in rhetorical, effusive and public voice in favor of a new urban sensibility, an awareness of individual moral complexity, an interest in vice (linked with decadence) and refined sensual and aesthetic pleasures, and the use of urban subject matter, such as the city, the crowd, individual passers-by, all expressed in highly ordered verse, sometimes through a cynical and ironic voice. Formally, the use of sound to create atmosphere, and of "symbols" (images that take on an expanded function within the poem), betray a move towards considering the poem as a self-referential object, an idea further developed by the Symbolists Verlaine and Mallarmé, who acknowledge Baudelaire as a pioneer in this regard.
Beyond his innovations in versification and the theories of symbolism and "correspondences", an awareness of which is essential to any appreciation of the literary value of his work, aspects of his work that regularly receive much critical discussion include the role of women, the theological direction of his work and his alleged advocacy of "satanism", his experience of drug-induced states of mind, the figure of the dandy, his stance regarding democracy and its implications for the individual, his response to the spiritual uncertainties of the time, his criticisms of the bourgeois, and his advocacy of modern music and painting (e.g., Wagner, Delacroix). He made Paris the subject of modern poetry. He would bring the city's details to life in the eyes and hearts of his readers.