Ellen MacGregor was born in Baltimore, Maryland and educated in schools in Garfield and Kent, Washington. She attended the University of Washington at Seattle, where she received a bachelor of science degree in library sciences in 1926. She also did postgraduate work in science at the University of California, Berkeley. In her career as a librarian, she worked in many locations including Hilo, Hawaii; Chicago, Illinois; and Key West, Florida. She was an editor of the Illinois Women’s Press Association’s monthly bulletin, Pen Points. In 1950, she began to publish comic short stories about the extraordinary and amazing travels of a prim New England spinster named Miss Lavinia Pickerell. The first in the series of science fiction novels for children for which Ellen MacGregor became famous, Miss Pickerell Goes to Mars, appeared in 1951. The books provided children with enjoyable fantasy literature containing accurate scientific facts. Three more Miss Pickerel novels followed before Ellen MacGregor's early death at age 47. McGraw-Hill, her publishers, searched unsuccessfully for someone to continue the series until 1964, when they selected Dora Pantell, a social worker and textbooks writer. She used notes left by Ellen MacGregor to create further Miss Pickerell novels until 1986.