Intellectual setting
Butler wrote "Gender Trouble" amid intense 1980s-90s feminist debate over essentialism, drawing on Foucault's account of power and discourse, structuralist and psychoanalytic theories of the subject, and earlier feminist critiques of a unified category of "woman."
Key ideas
Gender performativity
Butler argued that gender is not an expression of a prior, essential identity but is produced through the repeated, ritualized performance of gendered acts and norms, so that the appearance of a stable inner gender is itself an effect of that repetition rather than its cause.
Critique of the unified subject "woman"
Butler argued that feminist theory's assumption of a single, pre-discursive category of "women" as its political subject obscures how identity categories are themselves produced by discourse and power, and that this assumption excludes those whose identities do not fit its implicit norms.
Legacy
Butler's "Gender Trouble" is a founding text of queer theory and poststructuralist feminism, and their account of performativity has been foundational to gender studies, LGBTQ theory, and philosophy of social identity since the early 1990s.