Christopher Alexander, one of the most influential thinkers in urban planning and design in the 20th century, died in his home in England in March of this year at the age of 85. A professor of architecture at the University of California, Berkeley for many years, he is most well know for his seminal book, A Pattern Language, which seeks to understand the built environment as a lattice-work of patterns that we assemble. He is also known for his influence in New Urbanism, and field of urban planning that seeks to return development to a walkable, human scale. unPlanned sits down with Brent Ryan, professor of urban design and public policy at MIT, to understand this very interesting man and what he has meant to the profession of urban planning and design.