evidence: In a surprising email to me, Agatha Christie Limited (a private company set up by Agatha Christie prior to her death) confirms that this is indeed one of hers. They say the quote originated during an old press interview – but are unable to locate the source. John Curran, an expert on Agatha Christie with whom I share this bit of news, tells me he shall "remain dubious" until he sees the original citation. With Twain definitively out of the running for this quote though, and unless it can be proven otherwise, Agatha Christie deserves at least a tentative full-credit for now.