"Animals' Rights Considered in Relation to Social Progress" by Henry Salt presents a pioneering argument against speciesism, a concept that would not be named for another seventy-six years. Salt critiques practices such as vivisection, the exploitation of horses and wild animals, hunting, fishing, and the fur trade, while advocating for vegetarianism. His work is widely recognized as the first explicit exploration of animal rights, emphasizing the ethical treatment of all sentient beings.