New Criticism was a 20th-century approach to poetry and literary study that treats the poem as a self-contained work, best understood through close reading of its language, form, imagery, irony, and internal tensions rather than through the writer's life or historical background.
Critics in this tradition looked for how a poem's parts work together to create unity and meaning, and they often paid special attention to ambiguity, paradox, and pattern.
Example
Reading the sonnet as a complete design, she traced how the repeated image of winter, the turn in the final line, and the tight rhyme scheme all work together to shape its meaning without bringing in the poet's biography.