Double Eagle sees the focus put on the pilots of the Imperium, specifically a group of fighter- and bomber-pilots who were first seen in one of the Gaunt's Ghosts novels. As per usual, Abnett has superior character development. This book, as with all his others, is truly a page-turner.
Something of an aside to the Ghosts storyline, this novel takes place on a planet suffering from a Chaos invasion in the Sabbat Campaign that Abnett has written so much about. (In fact, there are some references to the Ghosts storyline, but not so that the reader is left confused.) As with Abnett's other works, we see comparatively little of the enemy in terms of internal thoughts, only getting that before they interact with the heroes. There is only one such villain, actually, an ace of aces who seems unstoppable. He makes several appearances, always defeating those he faces, or driving them to extreme measures to flee.
One of the primary characters is the flight commander of the Phantine XX fighter wing. She is a great character, mixing in-combat skill with concern for her wingmates. Others in the unit also provide great characters, the old nice guy, the new kid trying to prove himself. The planes are also like characters, given their jinxes and idiosyncrasies. The unit really is a whole, from machine, to tech, to pilots.
Another arc of the story deals with a bomber pilot who is in another unit. He was saved by one of the Ghosts in another novel, and feels he is on borrowed time, that he should be dead. He meets a woman who has lost pretty well everything, and they find in each other that which they were missing. This is really my favorite part of the book. The human side.
There is a great deal of air combat, which Abnett delivers with exquisite skill. I could feel all the losses and exult in the victories as though I were there. There are a number of close calls, tight squeezes, near-misses. All those things that make such situations interesting to read.
This novel shows again that Abnett is the best of the WH40k authors, at least in my opinion. Despite the lack of a well-determined enemy, this book is a great read. After all, the reader is supposed to feel for the Imperium, not those who hate all life. In that respect, the lack of depth in the enemy is perfect. However, as has been occurring more and more of late in new release books, there were a number of typos. Not the British-American differences in certain words, which I have grown accustomed to through Abnett and the rest, but simple lack of proofreading, I believe. The story was so great, though, that I overlooked that entirely in my rating.