With the Internationale Bauausstellung (IBA) Hamburg the Free and Hanseatic City dares a leap across the Elbe – to the Elbe islands Wilhelmsburg, Veddel, Kleiner Grasbrook and the Harburg castle island. From Hamburg’s “forgotten backyard” to the future lab of the metropolis: the IBA Hamburg focuses on the potentials of the international urban society – the COSMOPOLIS – the design of the „inner peripheries“ – the METROZONES – and the CITY UNDER CLIMATE CHANGE. Until the year 2013, when the Elbe islands will not only host the final presentation, but also an International Garden Show, numerous participants will work on the future of the metropolis. A series of publications will accompany the IBA on its way. Volume 1 features a retrospective of former International Building Exhibitions in Germany, an outlook on projects of the IBA Hamburg, and complex considerations of the metropolis phenomenon.