What is Modernism?

As part of Modern March I wanted to get a handle on what it means for a work to be "modern." The article at The Literature Network was quite helpful, though it has a lot of pop-ups.  The wikipedia article on Modernist Literature was also helpful.

• The art and literature of the early 20th century
• A response to the horror and upheaval of the "great war," and the world war that followed it
• A period of literary and artistic introspection
• A conscious rejection of the traditions of the past that strove to reflect a new reality
• A reaction to the restrictions of Victorian society and the excesses of Victorian art
• A movement that included the authentic voices of women and minorities
• A sparse style of language with a focus on images
• A period of experimentation with form and a desire to make work that was new

Among the big names of the period are T.S. Elliot, James Joyce, E. M. Forster, F. Scott Fitzgerald, Henry James, Ernest Hemingway, William Faulkner, Langston Hughes, and Virginia Woolf.