FROSSARD, Benjamin Sigismond. La Cause des Esclaves Nègres et des Habitans de la Guinée, portée au tribunal de la justice, de la religion, de la politique; ou histoire de la traite & de l'esclavage des nègres, preuve de leur illégitimité, moyens de les abolir sans nuire ni aux colonies ni aux colons, Lyon: Aimé de la Roche, 1789. 8° (195 x 120mm). Engraved frontispiece by Boily after Rouvier, with the 2 final leaves in volume II containing the approbation and privilège. Contemporary French mottled sheep, gilt fleuron in panels of flat spines, dentelle border round sides, red and green labels on spines. Only edition of this forceful plea for the abolition of slavery. Sabin 26013: 'An esteemed and valuable work, and one of the earliest on the evils of the slave trade; rare'. (2)