Lots of talk these days, as we all know, about "building that wall." But what about the borderwall that already exists between much of the U.S. and Mexico? And what about the cultures, events, art works, communities, and lives that are associated with this borderwall -- that is, with the various walls and fences running between these two countries? Our guest is Ronald Rael, an Associate Professor in the Departments of Architecture and Art Practice at the University of California, Berkeley. His new book is "Borderwall as Architecture: A Manifesto for the U.S.-Mexico Boundary" -- and it's a work that, per The Daily Beast, raises "questions that not many others are asking about the relationship between two countries that share 2,000 miles of border.... [This] book serves an important purpose." And further, as a writer for Architect Magazine has noted: "Part historical account, part theoretical appraisal, and part design manifesto, 'Borderwall as Architecture' is reminiscent of Rem Koolhaas' 'Delirious New York' in its sweeping assessment of both the sociocultural peculiarities and outlandish possibilities represented by a prominent structural element."