"In support of the rights of humanity, and of an injured and oppressed part of the human species" (iii), this pamphlet was addressed by Mullalla to the people of Ireland. Mullalla argues that: "Liberty can neither be bought or sold" (15), & agrees with Montesquieu that the idea of legal slavery should not be taken seriously. He suggests, like Raynal, that a general slave revolution was only awaiting a new Spartacus, and calls for recognition of the slave's right to defend his own freedom by force: "Whoever justifies so odious a system, deserves the philosopher's utmost contempt, and the negroe's dagger" (17). Mullalla saw current abstention campaigns as "inadequate" (24) against slave-owning interests, and calls for concerted action on the part of the nations of Europe. He concludes in support of the cause of Catholic emancipation in Ireland, where "slavery and oppression" (26) had been rife for many years.

James Mullalla was also the author of The political history of Ireland (Dublin: P. Byrne, 1793), A Defence of the French Revolution of 1789 (London: Henry Wilson, 1794) and A View of Irish Affairs since the revolution of 1688 (Dublin: T. Henshall, 1795).