Doherty has done his homework about the most important aspects of Akhenaten's great heresy, and given us a psychologially plausible portrait of a remarkable man who began as a truly spiritual religious believer, but ended up doing more damage to his own country than just about any other king in Egyptian history. The reader, through the eyes of his loyal friend, sees him evolve from a likeable, deeply devout young man to an ambitious prince convinced of his own divine destiny to a zealot and fanatical persecutor of the old religion. Since every effort was made after Akhenaten's reign to erase his memory, there has to be a lot of guess-work involved in reconstructing how he arrived at his monotheistic beliefs and then succeeded, temporarily, at least, in imposing them on his empire. But I wouldn't doubt that it took a few bloody battles and purges before he consolidated his power. And of course there would have been ambitious power-seekers supporting him, whether or not they believed his religious doctrines. I can also believe that the Egyptian people were initially glad to be free of the immensely wealthy and powerful cult of Amun, before realizing that they'd traded it for something worse. That often happens in a revolution that leads to a theocracy (as in contemporary Iran!)
Another reviewer has attacked Doherty for historical inaccuracies, but there is no such thing as an historical novel that can escape them completely. It's always easy and fun to play the "gotcha" game -- for example, when you sail from Thebes to Tel el Amarna, you're going downriver, not up, and you certainly would not have sailed past fields of maize 3000 years before Columbus discovered the Americas. Maize is a new-world plant. And yes, I agree that Akhenaten was probably not deformed. It's possible, if we can take his portraits literally, that he had Marphan's Syndrome, but if he had it, then so did "beautiful" Nefertiti, whose portraits are stylized in exactly the same manner. The elongated hands, feet and faces in Amarna-period art might simply be a new artistic convention, possibly an exaggeration of personal features in the manner of a political cartoon, although obviously with a more serious intent. Artists who were suddenly encouraged to pursue realism might have gone to the opposite extreme from the idealized representations of earlier kings. But I'm willing to give Doherty his artistic license, and accept in the context of the novel that Akhenaten was grotesque while Nefertiti was beautiful. It is, after all, called "historical fiction" for a reason.