"An Enquiry concerning Human Understanding" is a book by the Scottish empiricist philosopher David Hume, published in 1748. It was a simplification of an earlier effort, Hume's "A Treatise of Human Nature", published anonymously in London in 1739-40. Hume was disappointed with the reception of the Treatise, which "fell stillborn from the press," as he put it, and so tried again to disseminate his ideas to the public by writing a shorter and more polemical work.
This book has proven highly influential, both in the years that would immediately follow and today. Immanuel Kant points to it as the book which woke him from his self-described "dogmatic slumber."
The Enquiry is widely regarded as a classic in modern philosophical literature.