The author was W. Cleon Skousen. He was a senior FBI agent under J. Edgar Hoover. He taught agents and students the history of communism. The book, The Naken Communist, where the manifesto is printed, was a manuscript of his studies. He was encouraged to put this much into a published form, that omits volumes of his work, by Brigham Young University so the knowledge wouldn’t be lost.
As far as the Manifesto that you feel was an opinion, it can be found on Page 17 of The Naked Communist with the history of it’s origins:
Excerpt:
November 1874, the “Federal Just”, later known as the Communist League, invited Marx and Engels to particiate in their second congress as representatives of the Communist organizations in Brussels. Marx and Engels not only attended; but practically took over. The manifesto was written by Marx and Engels as the communist strategy, presented at the meeting and adopted as a declaration of principles as the “Manifesto to the World”. It was announced as the new program of International Communism.
NOTES - Various Related Info Possibly Related to the SDS/Weathermen
Joseph Stalin
Josif Vissarionovich Dzhugashvili (December 21, 1879 - March 5, 1953), better known as Joseph Stalin (Iosef Stalin in an alternative transliteration) was the second leader of the Soviet Union. He was also known as Koba (also Georgian folk hero; see: Koba[?]). The name Stalin (derived from combining Russian stal, “steel” with Lenin) originally was a conspiratorial nickname; however, it stuck to him and he continued to call himself Stalin after the Russian Revolution. Stalin is also reported to have used at least a dozen other names for the purpose of secret communications, but for obvious reasons most of them remain unknown.