Mary Bard Jensen (1904–1970) was a 20th-century American author best remembered today as the sister of Betty Macdonald (Mrs. Piggle-Wiggle, The Egg and I.)
Mary Bard was born in Butte, Montana in 1904, the eldest of five children. With their mining engineer father, the family traveled all over the country, moving so frequently that Mary did not complete one uninterrupted year of school until she was 13. After a year at the University of Washington and stints as a stenographer, filing clerk and switchboard operator, she finally settled on advertising and wrote radio commercials.
Bard was the author of the three volume Best Friends series for girls. She also wrote three autobiographical works: Just Be Yourself, The Doctor Wears Three Faces, and Forty Odd. Married to a doctor, she was the mother of three daughters.