Yet it is also easy to see why Ludwig Mies van der Rohe, a pillar of early Modernism and Johnson’s mentor, stormed out in a huff when he saw it. The house was famously influenced by Mies’s Farnsworth House, which was designed before Johnson’s Glass House but built, in Illinois, several years later, leaving the impression that the student had leapfrogged over his master. More important, Johnson’s vision lacked the intellectual rigor and exquisite detailing that were so critical to Mies’s genius. The steel I-beams that mark the corners of the Glass House are clumsily detailed — especially disconcerting in a work of such purity.