C.K. Prahalad and Stuart Hart’s seminal book The Fortune at the Bottom of the Pyramid gained a wide audience when it was published in 2004 and has continued to be widely read ever since. Its iconic phrase, “bottom of the pyramid,” entered the English lexicon. The book was a call to action to the world’s largest companies to develop new products for the four billion people living on $4 a day or less—a market representing what was in effect the new frontier for corporate expansion.