George Bernard Shaw once wrote: ÒIf you have an apple and I have an apple and we exchange these apples then you and I will still each have one apple. But if you have an idea and I have an idea and we exchange these ideas, then each of us will have two ideas.Ó Open Field is the Walker Art CenterÕs three-year experiment in participation and public space. Taking place outdoors in the summer months, the project invited artists and visitors to imagine and inhabit the museumÕs campus as a cultural commonsÑa shared space for idea exchange, creative gatherings, and unexpected interactions. The WalkerÕs backyard was home to numerous activities, from conversations to performances and temporary sculptures. This volume discusses Open FieldÕs genesis, exploring the meaning and impact of public practice for institutions.