“When they started this project, Damien and the screenwriter Josh Singer started with the only authorized biography that our dad ever participated in called First Man, and it’s a very heavy, dense book, but it’s full of detail, and that’s where they started,” Mark said at TIFF. “They spent two or three years after that going deep, getting the details in between the chapters, in between the words, in between the paragraphs, and I’m here to tell you that they got it right. And we absolutely would not be here today if they hadn’t, so I’m really grateful to them.”