Many of us spend more time at our desks than anywhere else. Theoretical physicist and mathematician Brian Greene takes us into his home office for a tour of his tidy workspace, in the second of Science Friday's Desktop Diaries series. Greene uses his desk mainly for calculations, often executed with pencil and paper--a tradition that dates back to his childhood when his father would give him 30-digit by 30-digit multiplication problems to work out. Greene's father, Alan Greene, was a composer, and his music features in this video.