Anna Blackwell (pseudonym, Fidelitas;[1] 21 June 1816 – 4 January 1900) was a British writer, journalist, and translator who focused on spiritual and social issues.

Their sister-in-law, Antoinette Brown Blackwell, was the first woman to be ordained as a mainstream Protestant minister in the United States.

[1] Blackwell was an Associationist being conversant with the social reorganization theories of Charles Fourier, and advocated cooperative methods as opposed to individual and competitive enterprise.

Some of our number were rich, some poor, the former keeping up the place, the latter earning their livelihood; none paid for board and lodging and all performed a certain amount of manual labor.

Thus one set of workers collected the lamps, another cleaned them, a third-myself among the number- trimmed the wicks, a fourth filled the receptacles with oil, and so on.

At the time of my stay I had under my care a young sister, and, as there was no room for her, I felt compelled to leave on my charge's account.

[7] In 1875, the Spiritualist Association of Great Britain offered two prizes for essays upon 'the Probable Effect of Spiritualism upon the Social, Moral, and Religious Condition of Society', the first of which was won by Blackwell.

She also translated Allan Kardec's works from the French, besides writing in the spiritual press numerous articles explaining and defending reincarnation, many years prior to the advent of Helena Blavatsky.

Blackwell also wrote and translated several works on social questions, her last book, entitled Whence and Whither having been published by G. Redway in 1898.

[3] Spence's Encyclopædia of Occultism (1920) mentions her briefly, only stating that Blackwell endeavoured without success to establish the doctrine of reincarnation in England.