A Warning is a 2019 book-length exposé of the Trump administration, anonymously authored by someone described as a "senior Trump administration official". It is a follow-up to an anonymous op-ed published by the New York Times in September 2018. The article, "I Am Part of the Resistance Inside the Trump Administration", described President Donald Trump's decision-making as uninformed and irresponsible, and said that many current members of the administration deliberately undermine his suggestions and orders for the good of the country.[1]