Information and communication technologies (ICTs) have been a remarkable success in Africa. In just 10 years--dating from the end of the 1990s--mobile network coverage rose from 16 percent to 90 percent of the urban population and by 2009 nearly half of Africa's rural population was also living within range of a mobile network. Large-scale investment in the sector across the continent has transformed telecommunications from a luxury enjoyed by a privileged few to a mass-market, low-cost service, used in villages and cities alike. Africa's ICT Infrastructure: Building on the Mobile Revolution charts this ICT revolution, reviewing the rapid growth in networks and the emergence of the mobile phone as a part of everyday life in Africa. It also tracks the policy and regulatory changes that have driven this growth: the liberalization of markets, the establishment of effective competition and the emergence of institutions to regulate the sector. Africa's ICT Infrastructure reviews how the investment in the sector has been financed and how the structure of the market has changed since the liberalization process started. It looks at the role of both private and public institutions as sources of financing for the sector and charts the emergence of investors from developing countries in leading the expansion of the sector across the region. In the context of these successful sector reforms, Africa's ICT Infrastructure addresses one of the key questions facing regulators and policy makers: how far will this process go in delivering universal access to telecommunications services? By adopting an innovative new spatial modeling approach, the authors have mapped existing mobile network coverage in Sub-Saharan Africa and estimated the limits of commercially viable network expansion. But at the same time as voice networks are expanding across the region, the focus of sector policy makers is turning to the Internet which is becoming increasingly important in the global economy. The authors use a similar spatial approach to analyze the commercial viability of wireless broadband networks in Africa and review the development of the region's fiber-optic network infrastructure which lies at the heart of broadband service delivery. Finally, Africa's ICT Infrastructure draws these experiences together and offers a set of policy recommendations that will support the continued development of the sector, particularly in the delivery of affordable broadband Internet.