Ruby Ferguson (née Ashby) was born in Reeth, West Yorkshire in 1899, as the daughter of a Wesleyan Minister. She attended Bradford Girls’ Grammar School and then read English at St Hilda’s College, Oxford between 1919 and 1922. After completing her MA, Ruby Ferguson moved to Manchester and started working as a secretary. Her writing was first published in the form of a regular column in British Weekly magazine, but her career really began when she entered some detective stories in a competition in the Manchester Evening News.

Her first full length novel was published in 1926, under the name R. C. Ashby, and she continued writing under this name until her marriage in 1934. It was after this that she started to write romantic novels, the most famous of which, Lady Rose and Mrs Memmary, has been reprinted by Persephone Books. The books for which Ferguson is best known are those about Jill Crewe and her ponies which she wrote for her step-grandchildren. Her final book, published in 1967, the year after her death, is titled The Children at the Shop and is a fictionalized autobiography of her childhood.

Ruby Ferguson

Jill's Gymkhana
A Stable for Jill
Jill has Two Ponies
Jill Enjoys her Ponies
Jill's Riding Club
Rosettes for Jill
Jill and the Perfect Pony
Pony Jobs for Jill
Jill's Pony Trek

Lady Rose and Mrs Memmary
The Moment of Truth
Our Dreaming Done
Winter's Grace
Turn Again Home
Apricot Sky
A Paintbox for Pauline
The Leopard's Coast
For Every Favour
Doves in My Fig-tree
The Cousins of Colonel Ivy
The Wakeful Guest
A Woman With a Secret
Children at the Shop: The Charming Autobiography of Childhood

R.C. Ashby

The Moorland Man
The Tale of Rowan Christie
Beauty Bewitched
Death at Tiptoe
Plot Against a Widow
He Arrived at Dusk
One Way Traffic
Out Went the Taper

Jane Badger Books' website contains an excellent feature on Ruby Ferguson and her pony books.

Wikipedia also has an article about Ruby Fergusson.