Buckle, Stephen. Hume's Enlightenment Tract: The Unity and Purpose of “An Enquiry concerning Human Understanding”, Oxford: Clarendon Press, 2004.

From the publisher:

This is the first full book-length study in forty years of David Hume’s Enquiry concerning Human Understanding-which, contrary to its author’s expressed wishes, long lived in the shadow of its predecessor A Treatise of Human Nature. Stephen Buckle presents the Enquiry in a fresh light, aiming to raise it to its rightful position in the history of philosophy. He argues that the Enquiry is not, as so often assumed, a mere collection of watered-down extracts from the earlier work. It is, rather, a coherent work with a unified argument; and, when this argument is grasped as a whole, the Enquiry shows itself to be the best introduction to the features of its author’s general philosophy.

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