Writers are raising doubts about the veracity of an eight-year-old book on playwright Tennessee Williams, author of A Streetcar Named Desire, Cat on a Hot Tin Roof, and other classics of the American theater.

In an article for the New Yorker, Helen Shaw examines James Grissom’s Follies of God: Tennessee Williams and the Women of the Fog, published by Knopf in 2015. In the book, Grissom writes that when he was a student at Louisiana State University in 1982, he sent Williams a fan letter, and Williams later met with him, asking him to interview actors, directors, and authors about what Williams meant to them.

Williams died in 1983.

In a starred review, a critic for Kirkus wrote of the book, “There have been plenty of books written about Williams over the past three decades, but few weave so many voices into an original and compelling portrait. Grissom honors the life and achievement of his doomed correspondent.”

Shaw writes that some readers who reviewed Follies of God on Amazon and GoodReads pointed out that the book didn’t contain endnotes.

“For a long time, the charge was ‘Why are there no source notes?’ Well, because I’m the source,” Grissom told Shaw. “It’s a memoir. It’s not a biography.”

John S. Bak, a professor and expert on Williams’ later career, told Shaw, “Everyone, probably, within the tight-knit community recognizes [Grissom’s] book as—oh, I don’t want to say ‘fluff,’ but as undocumented, and therefore perhaps unreliable.” And author Dotson Rader, a friend of Williams, told Shaw that Williams did not use cocaine, as Grissom claims in his book.

When Shaw asked to see evidence for the anecdotes and interviews in his book, Grissom initially balked but later provided her with some material. When she asked Grissom why he wouldn’t show her more evidence, Grissom replied, “I’ve also not shown you my penis. I’ve shown other people. You know, there are times and places for things to be shown.…I don’t understand someone just showing up out of thin air and demanding to see documents.”

Knopf provided a statement to the New Yorker about Grissom’s book, which reads in part, “In his contract with Knopf for Follies of God, James Grissom warranted that the content of the book was entirely factual. He stands by that guarantee.”

Michael Schaub, a journalist and regular contributor to NPR, lives near Austin, Texas.