The first version in book form appeared as an appendix in the third edition, in 1905, of a book called (in Russian) The Great in the Small: Antichrist considered as an imminent political possibility, by a Russian mystic named Sergei Nilus. The original manuscript, which has never been discovered, may well have been written in French (cf. Cohn, p 69) and translated into Russian. Cohn says (p 67) "It was Nilus's version, not Butmi's, that was to become a force in world history. That did not even begin to happen in 1905 . . . It happened only when the book reappeared, somewhat revised and enlarged, under the title [in Russian] He is Near, At the Door . . . Here comes Antichrist and the reign of the Devil on earth. And it happened because of the moment: 1917." Some say widespread attention to the Protocols began a little later, in 1918, after the defeat of Germany in World War I (cf. Herman Bernstein, The Truth About "The Protocols of Zion", 1935, p 50, quoting Count du Chayla, who knew Nilus personally).
In 1921, The Times of London published three articles written by the newspaper's Constantinople (now Istanbul) correspondent, Philip Graves, which showed that the Protocols had been extensively plagiarized from a book by a French lawyer and writer named Maurice Joly. The book by Joly was called (in French) Dialogues in Hell Between Machiavelli and Montesquieu. It was published in Brussels (Belgium) in 1864 (with a Geneva imprint, although the edition I have seen is dated 1868 and has a Brussels imprint). Cohn notes (p 74-5): "In all, over 160 passages in the Protocols, totaling two-fifths of the entire text, are clearly based on passages in Joly; in nine of the chapters the borrowings amount to more than half the text, in some they amount to three-quarters, in one (Protocol VII) to almost the entire text. This should be enough to demonstrate that plagiarism occurred.
There is one very notable difference between the Protocols as put forth by Nilus and the Dialogues as put forth by Joly. In the Dialogues there is no mention of Jews. These Dialogues were a political satire directed at the government of Napoleon III in France, during the Second Empire. Joly was given 15 months in prison by this government for his satirical effort. The author or authors of the Protocols, so far as they were plagiarized from the Dialogues, substituted Jews where Joly had (non-Jewish) members of the government of Napoleon III.