Introduction to the special issue of the Global crisis in housing affordability

This paper introduces the special issue on The Global Crisis in Housing Affordability in the International Journal of Urban Sciences in 2021. It provides the motivation of the special issue, and discusses main topics covered by papers in this issue, including a review of the current literature and conceptual discussions, the extent of housing affordability problems in both developed and developing countries, causes and consequences of these problems, and evaluations of policy measures.