A Treatise of Human Nature, published in three books in 1739-40, was the first major philosophical work by David Hume, who famously said that it 'fell dead-born from the press', leading him to recast his ideas in An Enquiry Concerning Human Understanding and An Enquiry Concerning the Principles of Morals.
Hume's mature philosophy was nevertheless substantively that of the Treatise, which sought to put philosophy on an experimental basis like that of the physical sciences, rejecting metaphysical speculation as futile. It includes Hume's first account of his famous problem of induction, arguing that our belief in cause and effect is based on habit rather than rational justification. It was this sceptical attack which Kant later said ' first interrupted my dogmatic slumber and gave my investigations in the field of speculative philosophy a completely different direction.'
Free online texts
Early Modern Texts: A Treatise of Human Nature, adapted and translated into modern English, by Jonathan Bennett. PDF format.
Gutenberg: A Treatise of Human Nature. Multiple formats.
University of Adelaide (Internet Archive): A Treatise of Human Nature. Multiple formats.
Wikisource: Treatise of Human Nature. HTML and other formats.
BBC Radio 4 In Our Time: David Hume. Melvyn Bragg with Peter Millican, Helen Beebee and James Harris.
PhilPapers: Hume - A Treatise of Human Nature - bibliography with open access option.
Philosophy Bites: Paul Russell on David Hume's Philosophy of Irreligion. Podcast with Nigel Warburton.
Physics Today: Albert Einstein to Moritz Schlick - comments on the influence of the Treatise on the theory of relativity.
The Great Conversation: Further reading at Tom's Learning Notes
John Locke: An Essay Concerning Human Understanding.
Kant: Critique of Pure Reason.
Kant: Prologomena to Any Future Metaphysics.