She is regarded by the British Spiritualist Movement as one of its finest exponents of mediumship in the 20th Century but skeptics have not been convinced by her alleged powers. She claimed both physical and mental mediumship, and the teachings of her guide, a native American Indian, known as Red Cloud, have been published. She toured the UK giving mediumship demonstrations for money. On 13 July 1930 Eight thousand people attended the Albert Hall for Arthur Conan Doyle's memorial service. Roberts claimed to witness Doyle's spirit in a chair.
Roberts wrote the book Forty Years a Medium (1960). The book was described in a review as non-scientific and was questioned how anyone apart from the author could take it seriously. The spirit guide of Roberts known as Red Cloud made false predictions. He predicted that World War II was not going to break out and that there was going to be peace. Roberts refused for her mediumship to be tested or observed by any scientist or psychical researcher. The Society for Psychical Research offered to test her abilities but she declined to be tested.
Roberts claimed to materialize an Indian spirit guide called "Red Cloud". Researcher Melvin Harris who examined some photographs of Red Cloud suggested that the face was the same as Roberts and she had dressed up in a feathered war bonnet.
- Red Cloud Speaks (1938)
- Forty Years a Medium (1959)
- Fifty Years a Medium (1972)
- Kelvin Jones. (1989). Conan Doyle and the Spirits: The Spiritualist Career of Sir Arthur Conan Doyle. Aquarian Press. p. 245. ISBN 978-0850308372
- John O'London's: For books and the arts. Volume 1. 1959. p. 179
- Geoffrey K. Nelson. (1969). Spiritualism and Society. Routledge & Kegan Paul. p. 162. ISBN 978-0710062529
- Estelle Roberts (1889-1970). Encyclopedia of Occultism & Parapsychology.
- Melvin Harris. (2003). Investigating the Unexplained: Psychic Detectives, the Amityville Horror-mongers, Jack the Ripper, and Other Mysteries of the Paranormal. Prometheus Books. p. 21. ISBN 978-0879753580