Philip Johnson was an American architect born in 1906 who is known for introducing the International Style of modern architecture to the United States. He began his career focusing on the stark glass and steel styles of Mies van der Rohe but later incorporated more ornamental historical elements. Johnson had a significant influence through his pioneering use of glass in buildings, experimenting with all-glass facades in projects like the AT&T Building, now the Sony Tower. He believed architecture was about organizing interior space and designed notable buildings like the Crystal Cathedral featuring dramatic glass structures.