An Essay on the Impolicy of the African Slave Trade. In Two Parts. London: Printed and Sold by J. Phillips, 1788. First English edition, a presentation copy inscribed "For Samuel Vaughan Esquire from the author, " with Samuel Vaughan's signature on the front paste-down; the first English edition was published the same year as the first American edition, with no priority established (the American edition was printed in Philadelphia with the addition of an essay by Brissot de Warville). Publisher's blue boards with cream (now darkened to tan) paper spine, housed in a custom quarter morocco clamshell box. 8 7/8 x 5 1/2 inches (22.5 x 14 cm); [11], iv, 134 pp. A fine uncut copy in original boards, minor toning. As noted, a presentation to Samuel Vaughan (who was a friend to Benjamin Franklin and George Washington); the front cover bears an inscription "James Wilson Esqr., Philadelphia, with a letter” written in elegant cursive on the front cover, directly beneath the faint initials “J.V.” (plausibly Samuel Vaughan's son John).

Clarkson famously experienced a Pauline moment while returning from Cambridge after receiving a prize for an essay against slavery. The realization dawned that "If the contents of the Essay were true, it was time some person should see these calamities to their end." At the moment when he realized that he had that moral obligation, the antislavery movement gained its greatest advocate. His initial publication was an expanded version of the Cambridge essay, and then, having researched for two years first-hand the iniquities of the slave trade, he issued the present work. Dedicated to Wilberforce, the Essay on the Impolicy of the African Slave Trade dismantles one by one the claims used to justify the trade, to devastating effect. This was to be followed in 1808 by his opus The History of the Rise, Progress, and Accomplishment of the Abolition of the African Slave-Trade by the British Parliament, which helped cement the concept of slavery as a moral crime.

This copy has an interesting and significant American provenance. Samuel Vaughan was a British merchant with plantations in Jamaica who, unusually for a planter, was opposed to the slave trade. He held close ties with George Washington, among other prominent figures. Indeed, he commissioned Gilbert Stuart's famous portrait of Washington that hangs in The National Gallery, and in another benefaction, gifted Washington a marble mantel for Mount Vernon. At some time after he received this copy from Clarkson, it was conveyed to Philadelphia, possibly by his son John. The Wilson who received this copy is most likely the Pennsylvania lawyer who was "one of the most influential members of the Constitutional Convention in 1787" and one of only six men to sign both the Constitution and the Declaration of Independence.