The Rights of Woman
Most writers in the late 18th and early 19th century were men, and a lot of the world frowned on women who wrote essays or poetry. Some women even published under fake, male names so that no one could give them a hard time about it.
Anna Barbauld had a lot to say about a lot of subjects, from slavery and religious freedom to the rights of women, and she never shied away from using her own name. She actually emphasized her own perspective as an intelligent, well-informed woman. She wanted the rest of British society to realize that a woman's perspective on the world was a valuable contribution to the literature and to political discussions of her day.