Analysis of literary texts that is based purely on the text itself and not historical context, the author's biography etcetera is not so much a "section" of literary theory
but an approach practised by several schools of literary theory. This approach is known as formalism, which Wikipedia defines as
a school of literary criticism and literary theory having mainly to do with structural purposes of a particular text. It is the study of a text without taking into account any outside influence.
Russian formalism (Russia, 1910s to 1930s) included critics such as Viktor Shklovsky, Yuri Tynianov and Roman Jakobson.
Some émigrés from this (rather loose) group later became members of the Prague linguistic circle.
However, the best known formalist movement is known as New Criticism.
The article Literary Theory in the Internet Encyclopedia of Philosophy says,
The "New Criticism," so designated as to indicate a break with traditional methods, was a product of the American university in the 1930s and 40s. "New Criticism" stressed close reading of the text itself, much like the French pedagogical precept "explication du texte." As a strategy of reading, "New Criticism" viewed the work of literature as an aesthetic object independent of historical context and as a unified whole that reflected the unified sensibility of the artist.
The term close reading (mentioned in a previous answer) comes from this school of literary criticism,
especially I. A. Richards' book Practical Criticism (1929)
and William Empson's book Seven Types of Ambiguity.
Less well-known, perhaps, is the German approach known as werkimmanente Interpretation. "Werkimmanent" means "what is intrinsic in the 'work'".
This approach emerged in Germany after World War II. One reason is that after the period of National-Socialism, critics wanted to exclude political, social and historical considerations from the study of literature.
There was probably also a more material reason for this: so many books had disappeared that accessing sources for the study of political, social and historical contexts was simply difficult.
Examples of books and articles from these schools of criticism (in addition to those already mentioned) include the following:
- Cleanth Brooks and Robert Penn Warren: Understanding Poetry (a textbook first published in 1938)
- Cleanth Brooks: The Well Wrought Urn: Studies in the Structure of Poetry (1947)
- René Wellek and Austin Warren: Theory of Literature (1948, with several later editions; Wellek came for the Prague linguistic circle; standard reference book)
- Wolfgang Kayser: Das sprachliche Kunstwerk. Eine Einführung in die Literaturwissenschaft (1948; many times reprinted; possibly never translated into English).
- W. K. Wimsatt: The Verbal Icon: Studies in the Meaning of Poetry (1954)
- W.K. Wimsatt, Jr., and Monroe C. Beardsley: "The Intentional Fallacy" and "The Affective Fallacy".