| title | creator | language | description | tableOfContents | contributor | subject | created |
| A Full Enquiry into the Nature of the Pastoral (1717) | Purney, Thomas | en | | | | | 2005-03-10 |
| An Enquiry into the Obligations of Christians to Use Means for the Conversion of the Heathens
In Which the Religious State of the Different Nations of the World, the Success of Former Undertakings, and the Practicability of Further Undertakings, Are Cons | Carey, William, 1761-1834 | en | | | | | 2004-03-01 |
| A Practical Enquiry into the Philosophy of Education | Gall, James, 1784?-1874 | en | | | | | 2009-01-13 |
| An Enquiry Concerning the Principles of Morals | Hume, David, 1711-1776 | en | | | | Ethics; Conduct of life | 2003-08-01 |
| An Enquiry Concerning the Principles of Taste, and of the Origin of our Ideas of Beauty, etc. | Reynolds, Frances, 1729-1807 | en | Augustan Reprint Society, publication number 27 | | Clifford, James L. [Commentator] | | 2004-09-17 |
| An Enquiry into the Truth of the Tradition, Concerning the
Discovery of America, by Prince Madog ab Owen Gwynedd, about the Year, 1170 | Williams, John, 1727-1798 | en | | | | Madog ab Owain Gwynedd, 1150-1180?; America -- Discovery and exploration -- Welsh | 2004-11-12 |