The book "Thoughts on Slavery" by the famous English preacher and theologian John Wesley highlights the problem of slavery from a moral and ethical point of view. The author considers the complex topic of slavery as a social evil, a violation of basic human rights and a leading moral problem. Proceeding from classical considerations about human rights and dignity, Wesley calls on his readers to think about the importance of respect for others and the fight against negative social phenomena. "Thoughts on Slavery" became one of the most influential works of the 18th century, which provokes deep thought and calls for action in the humanization of society.