I have to say first of all, what a fantastic choice of topic! It’s amazing what an influence ID have had in computer games and beyond, and I was delighted to find a book like this had been written.
And very well written it is too. Kushner has researched his topic in incredible depth, as is made clear from the author’s notes at the back of the book including how many people he interviewed. More than that he strings all the disparate details into a compelling story. Clearly the author is a fan of the two Johns and the other people involved, but he doesn’t shy away from presenting their flaws.
My only quibble is that there could be more detail in places, especially on Carmack’s significant technical achievements.