Calvin Augustine Frye (August 24, 1845 – April 26, 1917) was the personal assistant of Mary Baker Eddy (1821–1910), the founder of Christian Science.

[4] Calvin and his widowed sister, Lydia Roaf, first became interested in Christian Science through a sister-in-law, the wife of his brother Oscar Frye.

[3] Asa Eddy had gone to Lawrence shortly before his death to inquire about Calvin Frye as a possible secretary for his wife's work, and Rev.

[5] Frye lived in Eddy's homes at 569 Columbus Avenue, Boston, and later at Pleasant View, Concord, New Hampshire, and Chestnut Hill, Massachusetts.

Caroline Fraser, the most famous modern critic, called his notebooks "mysterious" in 1999, and claimed that at the time of writing, no outside scholars had been allowed to see the originals.