The US literary theorist Eve Kosofsky Sedgwick played a key role in the development of queer theory. She challenged heterosexual presumptions and the effects of labelling people by their sexuality, thereby redrawing the boundaries previously imposed on ideas of gender and sexuality.

Sedgwick teased new meanings from works by Dickens, Henry James and Jane Austen, and she was noted for the range of her interests, from Sophocles to the TV series ER.

She pioneered the concept of “homosociality”, a spectrum of desire extending from “men promoting the interests of men” to homosexuality, “men loving men”.

Although she concentrated on gay men, she also published important work on lesbianism, asserting that gay men and lesbian women are distinct groups and that understanding of them should be equallyseparate. In Between Men (1985) she looked at female relationships, linking lesbianism with women’s interrelations with their mothers, sisters and friends. A Dialogue on Love (1999) was her most personally revealing work, written after she had been given a diagnosis of breast cancer. She used her therapy sessions as a way of discussing her feelings towards death and her gender uncertainty while undergoing chemotherapy and after her mastectomy. Sedgwick was not a lesbian. Although she questioned her own and others’ sexuality, she was happily married to Hal Sedgwick, whom she wed in 1969. Rather, she identified herself as “a gay man”, distinct from identifying “with gay men”, thus placing her within her defined spectrum of sexuality.

Eve Kosofsky was born in 1950 in Dayton, Ohio. She grew up close to a toxic incinerator in an area that was a hotspot for breast cancer. She graduated from Cornell University with a BA in English in 1971 and then earned a master’s and a PhD in English at Yale. It was at these two institutions that French literary theories such as deconstruction first became popular in the English-speaking world. But Sedgwick said that she was not affected by this movement. She was more interested in how theories such as deconstruction combined with the close-reading skills used in new criticism.

From the late 1970s until the late 1980s she taught at Hamilton College, Boston University and the University of Massachusetts Amherst, where she produced works on classic authors, using close reading to uncover submerged plots. During this time she completed her influential anthology Between Men: English Literature and Male Homosexual Desire (1985).

From 1988 she was a professor in the English department of Duke University in North Carolina. During this time she wrote Epistemology of the Closet (1990), which argued that Western culture could be understood only by critically dissecting the socially constructed concepts of homosexuality and heterosexuality. She also published Tendencies (1993), Novel Gazing: Queer Readings in Fiction (1997) and a collection of poetry, Fat Art, Thin Art (1994).

Despite her illness she continued to write, publishing Touching Feeling: Affect, Pedagogy, Performativity in 2003.

She is survived by her husband, Hal.

Eve Kosofsky Sedgwick, academic and writer, was born on May 2, 1950. She died of breast cancer on April 12, 2009, aged 58