My fave Annie Jacobsen claim is that what crashed in Roswell in 1947 was a Nazi-designed flying saucer crewed by Soviet midgets or children who Dr. Mengele had surgically altered to look like aliens, because Stalin wanted to cause a repeat of the Orson Welles' War of the Worlds scare. So. Yeah.
The Annie Jacobsen discourse is not new to me. It is not the first case of a popular author publishing an alleged history book with, shall we say, claims that are difficult to substantiate.