Short answers, pulled from the story.
Literary criticism is the study, evaluation, and interpretation of literature, typically dealing directly with particular literary works. Literary theory is the more abstract philosophical analysis of literature's goals and methods. Some scholars treat the two as the same activity, as The Johns Hopkins Guide to Literary Theory and Criticism does, while others consider criticism a practical application of theory.
Literary criticism is thought to have existed as far back as the classical period. Aristotle wrote the Poetics in the 4th century BC, the earliest major surviving work of literary criticism. It introduced the concepts of mimesis and catharsis, which remain central to literary studies.
The New Criticism was a school of literary analysis that emphasized close reading of texts and rejected focus on authorial intention and reader response. It emerged in Britain and the United States in the early 20th century and was more or less dominant in the English-speaking academic world until the late 1960s. W. K. Wimsatt and Monroe Beardsley named its key prohibitions the intentional fallacy and the affective fallacy.
Northrop Frye published the Anatomy of Criticism in 1957, a highly influential work in which he observed that critics tend to embrace an ideology and judge literary works by how closely they adhere to it. His viewpoint became an important reference for modern conservative thinkers in the field.
During the Enlightenment period in the 1700s-1800s, rising literacy rates and the commercialization of literature brought criticism to a broader public through magazines, newspapers, and journals. Critics evaluated works partly on the author's religious beliefs alongside style and content. Jonathan Swift's Gulliver's Travels, for example, was condemned by one critic as "the detestable story of the Yahoos."
Baroque literary theory challenged the classical values of harmony, proportion, and decorum that had governed Western thinking about art. Its key concepts of conceit, wit, and wonder were fully developed in Emanuele Tesauro's Il Cannocchiale aristotelico, published in 1654. The work drew on Giambattista Marino's epic Adone and the philosophy of Baltasar Gracian to develop a theory of metaphor as a universal language of images.