Anna Riva (1922–2003) was the pen name of Dorothy Spencer, a well-known American occult author and manufacturer of hoodoo spiritual supplies. According to Catherine Yronwode, "Anna Riva" was a nom de plume that this author used only in her writing and business; Anna was her mother's name and Riva was her daughter's name.

According to Craft Magick, Dorothy Spencer was born in 1923 and began writing as Anna Riva in the 1960s.

^[1] In Spiritual Merchants, Carolyn Morrow Long described how the "1970s and 1980s saw the publication of a new crop of spell books" for products available from the same companies selling the books.

"The best-known of these writers is the extremely prolific Dorothy Spencer, who writes under the name 'Anna Riva.'"

Spencer's books contained collected spells from many traditions, including Neopagan sources, European occultism, and the Judeo-Christian grimoire tradition. They often included mention of African American folk magic as well as Haitian Voodoo.

In addition to writing books on magic, Spencer produced an extensive line of magical oils, incenses and powders which were sold by occult suppliers.

When Spencer retired in the late 1990s, her company, International Imports of Los Angeles, was purchased by Indio Products, which continued to manufacture spiritual supplies bearing the Anna Riva name, as well as keeping her books in print.

In 2000, the owner of Indio Products, Marty Mayer, stated that the woman known as Anna Riva was suffering from Alzheimer's disease. In Spiritual Merchants (2001), Carolyn Long wrote "Dorothy Spencer is now quite elderly and, unfortunately, suffers from Alzheimer's disease, so I was unable to interview her." She died in 2003.