The Eugenics Wars, Vol.2: A wasted opportunity and contradicts everything we know about Kahn in TOS and ST-II: TWOK. You would think that since it's about The Eugenics War that it would star Kahn... but no, he's hardly in it... instead the characters Gary Seven and Roberta Licoln are the main characters even though they should not be in this story at all. Apparently the Augments and everyone else are so stupid that only these two can save the world. TOS and the 2nd film very well stated that Khan had an empire, took over one-quarter of Earth's population, other nations combined their efforts to defeat them and while a ruthless tyrant, Kirk and the others reluctantly admit to having a degree of respect for what Kahn accomplished, despite his many faults and crimes.
In the book, Khan has no empire at all, he wins no battles, Khan and the Augments are just dumb and weak, in fact the book pretty much states that The Eugenics War wasn't really a big deal. Why? Because since it didn't happen in real life (there are so many references to the 90s), therefore it's just some small conflict that hardly anyone hears about... someone should have told the politically-correct left-wing writer, Greg Cox, that the ST universe is NOT OUR universe.
Years later when Kirk and the others are deciding on what to do with a planet that wants to become a member of the Federation, but this planet's population has genetic engineering and since the Federation outlawed that because of The Eugenics War, that lead to WWIII, the planet will be put under quarantine... but if the book made it seem that The Eugenics War wasn't that important, just skirmishes among minor warlords and Khan wasn't even known and forgotten... then the quarantine and the outlaw of genetic engineering is meaningless. One has to wonder how the Federation and Kirk even know anything about that war or Khan himself and the book in no way states that it's an alternate reality, this is supposed to be in the canon ST universe.