Goodrich was noted for her thesis, first presented in a 1986 book titled King Arthur, that the legendary monarch was not a myth, but a real person, who lived not in England or Wales, as conventionally understood, but in Scotland.
Her scholarly methodology involved back-translating Latin place names found in Geoffrey of Monmouth’s Historia Regum Britanniae to what she believed to be their Celtic originals.
When she was 5, an aunt gave her a copy of Alfred, Lord Tennyson’s book The Idylls of the King, and set her on a literary path.
The previous year, she had remarried, to John Hereford Howard, and began teaching French and comparative literature at the University of Southern California rising ultimately to an assistant professorship.
In it she wrote, “The hero myth may be the one that has most influenced culture down the centuries.” By 1986, now professor emerita at the Claremont Colleges, she had turned her attention full-time to the legend of King Arthur.
That year she told a Los Angeles Times reporter that she had discovered a void in Arthurian scholarship: “All the books on Arthur have been on the mythology, the legend,” but not the history.
It is so fundamentally unsound that one would take it as an elaborate joke.... For an Arthurian expert, reading this book is a nightmare: familiar details are there, but in the grossest confusion.
Her obituary in the Los Angeles Times stated that "the fact that her King Arthur findings contradicted those of other scholars did not trouble Goodrich".