This book addresses the phenomenon of urban informality which is prevalent in cities of countries in transition. It focuses on the city of Nairobi in Kenya. Urban informality is more evident on the outskirts of the city of Nairobi than within the city. Such informality outside the city is a result of the statutory planning provisions that began in the colonial era through post colonial period up to 1997. Dr. Ayonga argues that the dual land-use development approach which began during colonial rule created two divergent (urban and rural) land-use systems. Urban specific and rural specific control models cannot manage the emerging third zone of mixed land-use outside the city. He opines that the Physical Planning Act and the Town Planning Act have the same features that can only be relevant in urban planning and therefore the Physical Planning Act cannot resolve land use conflicts in the purely rural and emergent mixed sector. The author recommends that the two land use systems – urban and rural - be integrated by harmonizing components which create the duality. This book is a must-read for land use policy makers, urban managers, students and lecturers of urban and regional planning.