Nairobi today has over 10 000 multi-story tenement buildings, many of them offering single rooms and up to eight stories high. Privately owned and exploiting urban space to the maximum, these bear similarities to housing in rapidly industrializing 19th century tenement cities - New York, Glasgow, Berlin and others. This book explores the emergence of tenement markets across time and space. It focuses on two contrasting cities: Berlin, the largest and densest concentration of tenements in the late 19th century; and Nairobi, a city today increasingly shaped by tenements.