Near the end of his life, Sweeney wrote a controversial and factually disputed memoir of the atomic bombing and the 509th Composite Group, "War's End: An Eyewitness Account of America's Last Atomic Mission". In "War's End", Sweeney defended the decision to drop the atomic bomb in light of subsequent historical questioning. However, it was Sweeney's other assertions regarding the Nagasaki atomic mission, along with various anecdotes regarding the 509th and its crews that drew the most criticism. General Paul Tibbets, Major "Dutch" Van Kirk, Colonel Thomas Ferebee and others vigorously disputed Sweeney's account of events. Partly in response to "War's End", General Tibbets issued a revised version of his own autobiography in 1998, adding a new section on the Nagasaki attack in which he harshly criticized Sweeney's actions during the mission.