Illuminati: Fact of Fiction?

Upon reading Angels and Demons by Dan Brown the idea that illuminati really exist is very hard for me to digest .But apparently this secret organization has be around since the late 1700's. Their movement was founded on May 1, in 1776 and is commonly described as a movement of freethinkers and scientists. It is apparent that this group is intent on the overthrow of the church and funtion with intensive seceracy and stealth that makes them virtually impossible to infiltrate or even accidentally stumble apon their hushed society. In 1784 an order was issued and the French Revolution started, resulting in vast bloodshed and the murder of many kings. A German writer by the name of Zwack had compiled these orders into a book which contained the entire Illuminati story and was originally called the "Order of the Perfectibilists". So the story goes the carrier who was on his way from Germany to France was struck and killed by lightning. the police later found his body along with the subversive documents and turned them over to the proper authorities. Whether this is all true or just some conspiracy i don't think will ever know.