Imagism was an influential American system of poetics most active between its inception in 1912 and 1917. The term was initially contrived by poetry propagandist Ezra Pound as a means to sweeten the reception of Hilda Doolittle (H.D.)'s poems, thinking that her words would be better-received if they were believed to epitomise the poetic ideals of a new, exotic and avant-garde school of poetry. Imagism (or Imagisme, as it would be intially styled) claimed to follow as a development from the earlier French Symbolist poets (such as Charles Baudelaire and Stéphane Mallarmé), but billing itself as analogous to sculpture where Symbolist poems aspired to musicality. (Vorticism, a later kind of Imagism-for-elites-only, would go still further and consider itself in painterly terms.) Further influence would arrive from the foreign poetics, Greek fragments, Chinese and Japanese forms - especially the haiku - that Pound and H.D. studied as scholars, were inspired by and appropriated from.

Other poets directly associated with the Imagist movement included Richard Aldington, John Gould Fletcher, F.S. Flint, Amy Lowell, Harriet Monroe and William Carlos Williams while its influence can be seen in the works of unaffiliated poets Conrad Aiken, T.S. Eliot, D.H. Lawrence (invited by Lowell to give their methods a spin in a successful attempt with far-reaching ramifications to gain cachet for the movement by piggybacking on the success of an already-established writer), Marianne Moore and Wallace Stevens, among others.

Because the term was originally retroactively applied to H.D.'s already-composed works, for its first few years its definition (beyond applying to that particular batch of poems) was infuriatingly vague - bibs and bobs pulled from the Symbolist writings, and eventually mutterings about the importance of "the image" - Pound said that "an image is an intellectual and emotional complex in an instant of time," a description perhaps best illustrated by what is considered to be the first intentionally Imagist poem, his In a Station of the Metro.

The growing body of published Imagist work itself (the four Imagist anthologies Des Imagistes of 1914 and Some Imagists in 1915, 1916, and 1917 editions in addition to the independent publication of individual poems in literary magazines Poetry from 1912 on and The Egoist from 1914 on) began describing, if not defining, to the public what Imagism was, its main proponents continuing in an enigmatic vein, elaborating as to the magic formula of Imagism only in sideways allusions to inspirations such as the Symbolists and T.E. Hulme and in describing what it was against and stood contrary to, rallying against the "rather blurry, messy... sentimentalistic mannerish" thoughtlessness and simplistic Romantic optimism Pound felt dominating the literature of the early 20th century. In the March 1913 issue of Poetry, Pound claimed in a vague cop-out that the essence of Imagism was a "certain 'Doctrine of the Image,'" conveniently not "committed to writing" and, lest the potent power of this poetry get out of the hands of professional poets, Imagism "did not concern the public."

Unfortunately, the secret formula of Imagism did end up being loosed upon the world by Amy Lowell, the pretender and successor to Pound's Imagism (Pound taking the moral high ground, referring to the movement disparagingly from that point on as Amygism and her as a "hippopoetess") three years later. She would write:

    From the preface to the (1916) anthology, "Some Imagist Poets," there is set down a brief list of tenets to which the poets contributing to it mutually agreed. I do not mean that they pledged themselves as to a creed. I mean that they all found themselves in accord upon these simple rules.

    These principles are not new; they have fallen into desuetude. They are the essentials of all great poetry, indeed of all great literature.

      1. To use the language of common speech, but to employ always the exact word, not the nearly-exact, nor the merely decorative word.

      2. To create new rhythms - as the expression of new moods - and not to copy old rhythms, which merely echo old moods. We do not insist upon "free-verse" as the only method of writing poetry. We fight for it as for a principle of liberty. We believe that the individuality of a poet may often be better expressed in free-verse than in conventional forms. In poetry a new cadence means a new idea.

      3. To allow absolute freedom in the choice of subject. It is not good art to write badly of aeroplanes and automobiles, nor is it necessarily bad art to write well about the past. We believe passionately in the artistic value of modern life, but we wish to point out that there is nothing so uninspiring nor so old-fashioned as an aeroplane of the year 1911.

      4. To present an image (hence the name: "Imagist"). We are not a school of painters, but we believe that poetry should render particulars exactly and not deal in vague generalities, however magnificent and sonorous. It is for this reason that we oppose the cosmic poet, who seems to us to shirk the real difficulties of his art.

      5. To produce poetry that is hard and clear, never blurred nor indefinite.

      6. Finally, most of us believe that concentration is of the very essence of poetry.

      Lowell's elaboration upon many of these points can be further read up on at http://www.english.uiuc.edu/maps/poets/g_l/amylowell/imagism.htm

With these rules so plainly published, every scribbler who'd been holding their breath on the formal dictates of the Next Big Thing broke the floodgates and began submitting reams and reams of lousy poetry (though in accordance with the as it turned out inadequate dictates of the above Imagist manifesto) and Imagism as a movement became quickly discredited, Pound jumping ship in 1914 for his new movement Vorticism (essentially Imagism but only for those who could actually write and not merely for any monkey who could follow six rules) with sculptor Henri Gaudier-Brzeska and painter Wyndham Lewis in its journal BLAST. Imagism fell by the wayside as a distinct and admired movement and was dissipated to the four winds as one of the most persistent and influential schools of poetic thought throughout the remainder of the 20th century.