Iron production has played a part in the history of Africa for more than 2,500 years. The study of this specific human activity has demonstrated its exceptional significance, its historical continuity and an astonishing variability of practice. In Sub-Saharan Africa, metallurgists developed different ways to produce the same material: iron. They multiplied the technical choices to a degree unequalled on other continents. But what is the significance of such extreme diversity? In this chapter, four case studies representing different situations are detailed: in Dendi Country/Benin, where the question of the nature of the raw materials is considered; in Dogon Country/Mali, seven contemporaneous smelting traditions in a limited geographical area; at the Korsimoro site/Burkina Faso, five successive smelting traditions in the same place; and in the Bassar region/Togo, the impact of ancient and intensive iron production on the environment and on the technology. Based on these examples the chapter discusses the interpretation of diversity in terms of the history of technology and population dynamics.