It's five years since C.K.Pralahad's The Fortune at the Bottom of the Pyramid was first published, and an updated anniversary edition is now out. The new edition is greatly expanded from the first one, and in ways that make it a fascinating read.

The concept of 'bottom of the pyramid' businesses was catalytic half a decade ago. Pralahad both identified some emerging business models which successfully served very low income consumers; and also at the same time provided a focus and clarity for many other businesses which were just starting to recognize the potential of low income markets. A few companies had found transformative business models – Unilever's packaging, price points, marketing and distribution for its consumer products, the innovation of the very low cost pre-pay card in mobile telephony, for example. After the publication of the book, with its case studies, many other companies were encouraged to think creatively about the market opportunities.

So the bottom of pyramid concept is now a defining frame of reference in many emerging economies. It has served consumers in those countries well by making it apparent to businesses that there are good profit opportunities.

The new edition offers, as a result, many more case studies of successful bottom of the pyramid business model innovations. One aspect of these which is particularly interesting is the evolution of whole supply chains starting from one success, and the mutually reinforcing success of the companies involved. It's a great micro-level case study of how the virtuous circle of endogenous growth gets started. Another lesson is the role information technology has played in making bottom of the pyramid business feasible, due to the cost reductions and scope for co-ordination.

I was struck, however, by the great preponderance of case studies from India, and elsewhere in Asia. It's not clear whether this is just an accident of where the research possibilities were easiest, or rather reflects the importance of the scale and growth of the Indian and other Asian economies. Scale is often under-estimated as a factor in the success of an economy – it's certainly important in the US lead in productivity. I'd like to understand better whether the opportunities for bottom of the pyramid business in African countries would be released by some economic reform, of the kind India introduced in 1991, or whether instead they are inherently limited by the small size and geographical distance from large markets of African economies. And if the latter, the implications for Africa's need for a genuine regional economic union are pretty powerful.

Anyway, this goes beyond the scope of what the author is trying to do in this book. The case studies in the new edition will be of interest to those who've read the first edition as well as new readers. There's also a CD with video case studies.