Daniel 2 and Daniel 7 are very similar.  Both  chapters talk about the world empires that precede and prepare the way for the kingdom of the great King, Jesus Christ.  Four beasts are spoken about in Daniel 7, beasts that represent Babylon, Media-Persia, Greece, and Roman.  The Roman Empire has three phases, the distant or historical one, the democratic one, and the dictator one, as the Beast or Antichrist will reign for a period of 42 months, which is just prior to the Coming of Jesus Christ when He sets up His kingdom.  A person cannot clearly understand the future unless he understands Daniel 7!