Short answers, pulled from the story.
Thomas Dunne Books was an imprint of St. Martin's Press, itself a division of Macmillan Publishers, that published popular trade fiction and nonfiction from 1986 until April 2020. St. Martin's Press eliminated the imprint as part of a job reduction and hiring freeze caused by the economic pressures of the COVID-19 pandemic.
The imprint dropped the book after it was revealed that Irving had ties to the Institute for Historical Review, described as the literary center of the United States Holocaust-denial movement. The book had been signed in 1996.
In October 1999, St. Martin's Press recalled and destroyed copies of Fortunate Son: George W. Bush and the Making of an American President after it emerged that its author, J. H. Hatfield, had served prison time for a car-bombing attempt on his former boss's life and had included an anonymous accusation about Bush. A St. Martin's executive editor resigned in protest over the publication.
Thomas Dunne Books published a wide range of authors, including Joe Haldeman (The Forever War), Bernie Sanders (Our Revolution: A Future to Believe In), Ralph Nader, William Shatner, Michael Palin and the members of Monty Python, Paul Beatty, and Homer Hickam, among others.
Macmillan Films was a production venture launched by Thomas Dunne Books in October 2010. It produced the docudrama series Gangland Undercover, based on the book Vagos, Mongols, and Outlaws: My Infiltration of America's Deadliest Biker Gangs by Charles Falco and Kerrie Droban, which the imprint published in 2013. It was later renamed Macmillan Entertainment.
In June 2016, the trade publication PublishersLunch reported that Thomas Dunne Books had been downsized to four employees. The imprint was closed entirely in April 2020.