Home, wrote Robert Frost, is the place where, when you have to go there, they have to take you in. And yet the idea of home has, in the modern world, become extremely problematic.

Robert Frost's words tellingly illustrate the centrality of home to the human experience, as an unconditional haven that one simply has, without having to earn.

Yet, we live at a time when the idea of home has become extremely problematic. Our homeless fill America's streets and shelters; the comfort of home is increasingly threatened by urban violence; and the world-wide plight of those exiled or...