Pegi Williams Book Shop began on 12th September 1987 when Pegi, who began her work in Children's Literature at the Loxton Institute Library (Riverland South Australia) in the early 1940's, and James, her nephew who started working with Pegi at The Children's Bookshelf of Australia in 1982, opened their own shop and business at Walkerville (in the Adelaide metropolitan area).

Pegi's family moved to Adelaide in 1946 where she joined the staff of E.S. Wigg and Son (Educational Booksellers) and Pegi's lifetime career in the Children's Book Trade commenced. Her work included consulting kindergartens and primary schools in South Australia and Northern Territory, recommending books for specific requirements and selections for school libraries as her judgement was relied upon heavily.

After 41 years in the book trade, Pegi and James officially opened Pegi Williams Book Shop on 12th December 1987 with the help of a couple of friends (Colin Thiele cut the ribbon, Max Fatchen ate the cake) and continued to provide their service and knowledge of Children's Literature to schools.

Pegi's career spanned 52 years, including 42 years of committee service to the South Australian Branch of the Children's Book Council, an Order of Australia Medal 1992 for her services to children's literature, and the Australian Booksellers and Publishers Association's 'Pixie Award' for dedicated service to the promotion of Australian Children's Books in 1995. In October 1998, Pegi tragically died in a car accident.