The Preface of The Picture Of Dorian Gray by Oscar Wilde could be considered the manifesto of Aestheticism movement.
The genre of the text excludes the presence of figures of speech. The text is structured in many short sentences arranged like a list. Every sentence presents an aesthetic principal.
The Preface underlines the importance of artist instead of poet. The artist is who makes his life different form the others and who creates beautiful things, not only reflections on his inner side (The artist is the creator of beautiful things.). The artist is not more he who expresses his condition through his art as in Romanticism happens. Only a few people can become artists: everyone who can take the beauty from art is a potential artist. The ability to render a work of art is important in Aestheticism: a work of art can be good or bad (There is no such thing as a moral or an immoral book. Books are well written, or badly written. That is all.). There are any messages, ethical conceptions or meanings in art, the art is importante because it is beautiful. If something is not beautiful it is not art (No artist has ethical sympathies. An ethical sympathy in an artist is an unpardonable mannerism of style. ).
The central part of The Preface focuses its attention on the figure of Caliban, a Shakespearean character who becomes pretext to talk about nineteenth century and its relationship with Romanticism and Realism (The nineteenth-century dislike of Realism is the rage of Caliban seeing his own face in a glass. The nineteenth-century dislike of Romanticism is the rage of Caliban not seeing his own face in a glass. ). Both Realism and Romanticism reveal an unliked reality, so they are refused from the XIX century as Caliban refuses to look himself in front of the mirror (he would see his face but it is angry for his ugliness).
According to aesthetic concept of art this text has not got any message, it is only a list arranged in different and shortr points.