Let's just get this out of the way now: regardless of the impression the cover might give you, this book is not a behind-the-scenes account of the making of Evangelion. Evengelion doesn't even come into play until near the end of the book where it acts as a sort of climax to the story -- the point at which the animation studio has finally reached its (arguable) pinnacle of fame and success. But there is a lot that happens prior to Eva, and it's all well worth reading.
This book is the story of the birth and development of Gainax -- the animation studio behind classics like Gunbuster, His and Her Circumstances, and of course Evangelion. But this is by no means an objective history. It's told from the point of view of Yasuhiro Takeda, who played a major role in founding the company, but whose name many anime fans -- especially those in the US -- probably don't readily recognize. He basically had a management role more than a anime creation role. He helped produce and run the famous Daicon III and Daicon IV conventions, as well as gather up all the major players that would eventually form the Gainax animation studio.
He admittedly tells the history from his own point of view, with all of the qirks, biases, and potential inacuracies that may come with it.
The thing that may frustrate fans the most about this book is that it covers more than just the animation studio itself. The author was also in charge of running an anime merchandise store as well as a series of conventions. Plus there are some personal stories about when the author had bouts of apathy or depression. And although it helps give a bigger picture of exactly what was going on, at times I just wished he would say (if he knew) what was going on over at the studio.
But among all of that subjectivity there really are some great stories and intriguing info. Plus, there's mention of plenty of big names that many fan will recognize. It's cool to see how so many famous directors got their start there, and how some big-name studios were actually offshoots of Gainax.
At the end of the book there's an interview with Hiroyuki Yamaga, Takami Akai, and Hideaki Anno where they talk about Takeda and how he fit into the group. It really helps round things out by giving you an outside perspective of the author.
All in all, it was a good, enjoyable, well written, insightful book. And it's got enough history and behind-the-scenes anecdotes to keep most any anime fan interested. Even the more personal moments, while frustrating, did not leave me without empathy for the author. Overall, I'd definitely recommend this for those interested in knowing more about Gainax and how it got its start.