The modernist movement developed in the first half of the twentieth century, influenced by the impact of Freud's psychonanalysis and the shock of the carnage of the First World War. T.S. Eliot, Ezra Pound, James Joyce, Virginia Woolf are usually cited as the major British modernists, while William Carlos Williams, Hernest Hemingway, William Faulkner and John Dos Passos are considered American examples of the movement.
As with all the labels that we apply to literary movements, Modernism includes a wide variety of texts and tendencies. The movement was far from homogeneous. However, a few common element also emerge such as the importance of the human unconscious, a sense of fragmentation both in society and within man's psyche, a constant effort to experiment with and innovate narrative techniques. Modernism thus rejects linear, logical developments and the conventional chronological expostion of events in favor of more complex structures that can better reproduce the depths of the unconscious. One of the literary techniques that some modernists authors adopted to this end was the stream of consciousness which strives to record the apparently inconsequential flow of associations passing through a chacter's mind.
Einstein's theory of relativity also played a role in influencing modernist mindset. While representations of time are portrayed as more cyclical or circular in texts like "To the Lighthouse," the fragmentation of existence" also speaks to historical time. Don't forget Joyce's "Ulysses"—a novel that centers on the construction of history while also asking questions about who writes history.
Non-linear time is also expressed in art and music. The Impressionists (movement within Modernism) definitely move away from "representation." By playing with light and dark, images reveal instead multiple truths and perspectives, suggesting that perception is relative, and that no one truth prevails.
Basically, it seems that the Modernist Movement, can be viewed as a movement that questions ideas about unity and wholeness-one that expresses the breakdown of the master narrative of earlier Victorian era.