He said he wanted no posthumous publications. But on Thursday, more than over 30 years after his death, Michel Foucault had a new book, “Confessions of the Flesh,” published in France by Gallimard.

Foucault’s unfinished investigation into the topic of sexuality in early Christian thought and practice is the fourth book in his “History of Sexuality” project. The three previously published volumes addressed sexuality during the modern period, from the 17th century to the mid-20th century; in ancient Greece; and in the Roman world. In them Foucault hoped to explain how sexuality became an object of scientific study and a subject of moral preoccupation.

Foucault was unable to finish “Confessions of the Flesh” before his death in 1984 from an AIDS-related illness.

The decision to publish the book was spurred by the sale in 2013 of the Foucault archives, which contained both a handwritten version of “Confessions of the Flesh” and a typed manuscript that Foucault had begun to correct, to the National Library of France by his longtime partner, Daniel Defert. Once that material became available to researchers, Foucault’s family, who hold the rights to his work, decided it should be shared more widely.