Many companies today embrace some form of continuous improvement process, under which they strive to make their products, services and systems better over time. The CIP concept seems very professional and corporate, but former Dollar General Corp. chief executive officer Cal Turner Jr. had a blunter version of the same idea.

“Would you like to know the real strategic genius of Dollar General?” Turner once asked the chairman of Procter & Gamble Co., who was visiting his office. “Well, our past has always been screwed up, and every year we just selectively unscrew a bit.”

Turner tells that story in his new book, My Father’s Business: The Small-Town Values that Built Dollar General into a Billion Dollar Company.

Dollar General was founded in 1939 by Turner’s father, Cal Turner, and grandfather, James Luther Turner, who had a third grade education but the instincts of an entrepreneur. The company had its start as a Depression-era business that bought inventory from failed stores and sold the merchandise to other, still viable, retailers. J.L. Turner and Son, founded in Scottsville, Ky., later became a retailer itself, and the big change came in 1955, when Cal Turner Sr. decided to open a store inspired by the “Dollar Day” sales held at the time by the big department stores in Nashville and Louisville, Ky. Why not open a store where it was Dollar Day everyday — where everything always sold for $1? The first Dollar General store opened on June 1, 1955, and it was an immediate hit.

Cal Turner Jr. joined the company as an executive in 1965. He became company president in 1977, and later was named chairman and chief executive officer. As its subtitle suggests, the book describes how the small town values he learned growing up helped him guide Dollar General to success, even as he was forced to fire his brother and make his father resign in order to transform the company from a chaotic family business into a successful public corporation.

Turner also details what he meant by the ideal of “selective unscrewing,” which was partly about realizing that the company had never been run to its full potential, and that management needed to be willing to take risks and embrace change, but also remain willing to learn from the frontline employees who deal directly with customers.