Here is one of the original architectural drawings done for the Empire State Building by William Lamb:
Scott Christianson wrote a brief piece (taken from his new book 100 Documents That Changed the World: From the Magna Carta to Wikileaks) on how the building was designed and built. The whole thing happened incredibly fast: the first architectural contract was signed in September 1929 and after only 410 days of construction, the building was opened in May 1931.