I quote the Wiki on this since it's pretty mainstream now.
Elements of the text in the Protocols were plagiarized from the 1864 book, Dialogue aux enfers entre Machiavel et Montesquieu (Dialogue in Hell Between Machiavelli and Montesquieu), written by the French satirist Maurice Joly. Joly's work attacks the political ambitions of Napoleon III using Machiavelli as a diabolical plotter in Hell as a stand-in for Napoleon's views. Jews do not appear in either work. Since it was illegal to criticize the monarchy, Joly had the pamphlet printed in Belgium, then tried to smuggle it back into France. The police confiscated as many copies as they could, and it was banned. After it was traced to Joly, he was tried on April 25, 1865, and sentenced to 15 months in prison at Sainte-Pelagie. Joly committed suicide in 1878.
The original source of the plagiarism has been identified as an 1864 book by Maurice Joly titled The Dialogue in Hell Between Machiavelli and Montesquieu, a satirical attack against the ambitions and methods of French Emperor Napoleon III. In the book, Machiavelli represented Napoleon III, and described a series of steps that he intended to take to become ruler of the world. The Joly book was in turn based on material borrowed from a popular novel of the time by EugÃ¨ne Sue titled The Mysteries of the People, in which those plotting to rule the world were the Jesuits instead of Napoleon III. Neither the Joly book nor the Sue book mentioned either Jews or Masons.
I had read all of this long before it hit the Wiki. Of course, this is all secondhand at best. I don't have the original sources, but the Joly work is still extant.
This is one of those controversial things that can be used to throw people off staring straight at the truth of the Zionist Project and the evil it has clearly done in Palestine. If the Protocols didn't exist, there would still be Zionism, the Likud, Christian-Zionists, AIPAC, etc.
The Zionists love to use it so they may get anti-racists to distance themselves for fear of guilt by association. If the Protocols was the creation of racists and ethnic bigots against Jews, then no one should have anything to do with anyone questioning what the Zionists (who do not represent all Jews – not even close) are doing or have done. I don't fall for the trick. I take information and to the best of my ability, divide the false from the true. I don't run from the truth.
So, I don't refer to the Protocols as authoritative other than to say that it describes a plan for domination that is universal in the hands of any would-be dictator. It's all quite Machiavellian actually.
That's why it parallels what actually happens. There are only so many ways to subvert a people to weaken them to come to control them.
There's a fairly large group on Facebook named, "The Protocols of the Learned Elders of Zion." I didn't join, nor will I.