I found this to be most nitty-gritty, detail-filled collection of case studies for business operations at the Bottom of the Pyramid. It was published after Havard Business School's Conference on Global Poverty: Business Solutions and Approaches in December 2005. A small sampling of chapter titles gives an idea of the valuable information presented: "Understanding Consumers and Retailers at the Base of the Pyramid in Latin America", "Creating a Market for Affordable Housing", "Viable Business Models to Serve Low-Income Consumers: Lessons from the Philippines". There are used copies available through Amazon.
It would be impossible to include all the specific insights I gained from this read. I read the book thinking of my own projects and, time and time again, found specific examples of businesses that developed innovative ways to overcome the same problems I face. If not the same problems, it at least forced me to ask myself questions if I was ready for the problems ahead. I would therefore recommend the book to managers and entrepreneurs who are beginning projects at the BOP for a one-stop overview of what has worked before and to get a feeling for the mentality that will lead to success.
For more details from the conference abstracts and powerpoint slides are available through Havard's Social Enterprise Initiative website.