"The Archæology of Knowledge" by Michel Foucaul,1969

He held a chair at the Collège de France with the title "History of Systems of Thought," and also taught at the University at Buffalo and the University of California, Berkeley.
Foucault is best known for his critical studies of social institutions, most notably psychiatry, medicine, the human sciences, and the prison system, as well as for his work on the history of human sexuality.
His work on power, and the relationships among power, knowledge, and discourse has been widely discussed.
In the 1960s Foucault was associated with Structuralism, a movement from which he distanced himself.
Foucault also rejected the post-structuralist and postmodernist labels to which he was often later attributed, preferring to classify his thought as a critical history of modernity rooted in Kant.

Foucault is particularly influenced by the work of Nietzsche; his "genealogy of knowledge" is a direct allusion to Nietzsche's genealogy of morals. In a late interview he definitively stated: "I am a Nietzschean."

In 2007 Foucault was listed as the most cited intellectual in the humanities by The Times Higher Education Guide.
One of Foucault's main arguments is that the construct of language, seemingly neutral "knowledge" and "institutions" who disseminate, can be used to disempower, discriminate, intimidate and tacitly oppress "minorities" and others regarded as "different" to the norm.
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Published in 1969, this volume was Foucault's main excursion into methodology, written as an appendix of sorts to Les Mots et les choses.
It makes references to Anglo-American analytical philosophy, particularly speech act theory.
Foucault directs his analysis toward
-the "statement" (énoncé),
-the basic unit of discourse.

"Statement" has a very special meaning in the Archaeology:
it denotes that which makes propositions, utterances, or speech acts meaningful.

In contrast to classic structuralists, Foucault does not believe that the meaning of semantic elements is determined prior to their articulation.
In this understanding, statements themselves are not propositions, utterances, or speech acts.
Rather, statements constitute a network of rules establishing what is meaningful, and these rules are the preconditions for propositions, utterances, or speech acts to have meaning.
However, statements are also 'events', because, like other rules, they appear at some time. Depending on whether or not it complies with these rules of meaning, a grammatically correct sentence may still lack meaning and, inversely, a grammatically incorrect sentence may still be meaningful.

Statements depend on the conditions in which they emerge and exist within a field of discourse; the meaning of a statement is reliant on the succession of statements that precede and follow it.
Foucault aims his analysis towards a huge organised dispersion of statements, called discursive formations. Foucault reiterates that the analysis he is outlining is only one possible procedure, and that he is not seeking to displace other ways of analysing discourse or render them as invalid.

According to Dreyfus and Rabinow, Foucault not only brackets out issues of truth (cf. Husserl), he also brackets out issues of meaning.
Rather than looking for a deeper meaning underneath discourse or looking for the source of meaning in some transcendental subject, Foucault analyzes the discursive and practical conditions for the existence of truth and meaning.

In order to show the principles of meaning and truth production in various discursive formations he details how truth claims emerge during various epochs on the basis of what was actually said and written during these periods of time.

He particularly describes the Renaissance, the Age of Enlightenment, and the 20th century. He strives to avoid all interpretation and to depart from the goals of hermeneutics. This does not mean that Foucault denounces truth and meaning, but just that truth and meaning depend on the historical discursive and practical means of truth and meaning production. For instance, although they were radically different during Enlightenment as opposed to Modernity, there were indeed meaning, truth and correct treatment of madness during both epochs (Madness and Civilization).

This posture allows Foucault to denounce a priori concepts of the nature of the human subject and focus on the role of discursive practices in constituting subjectivity.
Dispensing with finding a deeper meaning behind discourse appears to lead Foucault toward structuralism. However, whereas structuralists search for homogeneity in a discursive entity, Foucault focuses on differences.
Instead of asking what constitutes the specificity of European thought he asks what constitutes the differences developed within it and over time.

Therefore, as a historical method, he refuses to examine statements outside of their historical context: the discursive formation.

The meaning of a statement depends on the general rules that characterise the discursive formation to which it belongs.
A discursive formation continually generates new statements, and some of these usher in changes in the discursive formation that may or may not be adopted.
Therefore, to describe a discursive formation, Foucault also focuses on expelled and forgotten discourses that never happen to change the discursive formation.
Their difference to the dominant discourse also describe it.
In this way one can describe specific systems that determine which types of statements emerge.

In his Foucault (1986), Deleuze describes The Archaeology of Knowledge as "the most decisive step yet taken in the theory-practice of multiplicities."