What has the author Warren Hastings written?

Warren Hastings was a British East India Company administrator, not an author. He is best known as the first Governor-General of Bengal (1772-1785) and for his impeachment by the British Parliament, which was a significant event in British history.

He didn't write any books or literary works. The name you may be thinking of is another famous author, E.F. Benson (Edward Frederic Benson), who wrote a well-known novel titled "The Luck of the Vails" which featured a character named "Warren Hastings." This character is loosely based on the real historical figure.