And Let the Earth Tremble at Its CentersProfessor Juan Manuel Barrientos prefers footsteps to footnotes. Fighting a hangover, he manages to keep his appointment to lead a group of students on a walking lecture among the historic buildings of downtown Mexico City. When the students fail to show up, however, he undertakes a solo tour that includes more cantinas than cathedrals. Unable to resist either alcohol itself or the introspection it inspires, Professor Barrientos muddles his personal