Meaning of Bureaucracy

What is "bureaucracy," and why do we have it? What are the components of the U.S. executive bureaucracy, how has our bureaucracy changed over time, and why? How do Congress, the President, and the Courts control bureaucracy -- and how effectively? The president’s former Chief Strategist, Steve Bannon, has said he aims to “deconstruct the administrative state.” How might the President Trump attempt to do so? What opposition or resistance might he encounter?