Half the world's population now resides in cities, which are expanding at an unprecedented rate. Close to one billion people live in crowded, unhealthy, informal settlements--commonly referred to as slums--many of which lack security of land tenure, adequate housing, sanitation, clean water and electricity. Experts estimate that by 2030, more than two billion people will be living in these slums. In 2007, "Design for the Other 90%" explored design that helps provide better access to food, water, shelter, health, education and energy to those who most need them. "Design with the Other 90%: Cities" is the second installment in Cooper-Hewitt's ongoing and acclaimed exhibition and book series. It looks at some of the myriad challenges created by accelerated urban growth and presents design solutions that address the consequences. Exploring the multidisciplinary, overlapping relationships between urban planning and design, education, social entrepreneurship, climate change, sanitation and water, migration, public health and affordable housing in these communities, "Design with the Other 90%: Cities" looks at the efforts of international and locally based organizations, designers and communities collaborating with settlement residents to give them a chance at a more prosperous life.