"The Technocracy is wrong." The Void Engineers start out with a strong critical statement. Of course, they don't mean this morally, they mean it in the sense of incorrect. The Technocracy's fears, echoed in every other Revised Convention book, that the Void Engineers might abandon the Union, are baseless. Instead, the Void Engineers are clinging to it, desperately trying to keep things together because only with the Union can they keep Earth safe from entirely new classes of threat.
The Void Engineers were hit hard by the Dimensional Anomaly, and this book delivers on those chases beautifully. From the opening fiction (and the closing) showing a group of Void Engineers (and an Iteration X stowaway) to the text of the book, lots of changes are explored and the Void Engineers will never be the same. It even closes in the last sentences with the last Revised advancement of the meta plot: the Nephandi retaking Mus from the Technocracy, putting in another chapter of the saga started in the Mage 2nd Edition core book's opening fiction.
The book is organized similarly to other Convention books, but it has an extra chapter in it. It starts with a history of the Void Engineers, particularly updated to the present, discussing some of the changes (Existential Threats Directorate instead of DSEATC, etc) and it is the first of the new Convention books to have a jargon section, which makes an excellent reference (rather than having to skim through to find things like rankings and other bold-faced terms like in the others). The Void Engineer takes on the other Conventions and the Traditions are quite different from other Conventions: the Void Engineers value openness and science so they like the Progenitors and hate the New World Order (especially with all the deprocessing that they need to do). They tolerate the Syndicate and worry about Iteration X. Oddly, among the Traditions, the Void Engineers have grown close to the Euthanatos, their fellow fighters against Threat Null. It's also mentioned that working with Etherites against Null is extra effective.
Chapter 2 provides rankings, honors and awards, the requirements to become a Void Engineer, and a discussion of the methodologies. It's well-done, but nothing that isn't the same as the other Convention books, just about the Void Engineers instead of a different Convention.
Chapter 3 is something different. Chapter 4 will contain more standard things (procedures, devices, etc) but Chapter 3 focuses on the Void Engineer Cosmology and what is out there. It even has a map, placing the Horizon at the asteroid belt (and talking about how it has moved over time, and the Void Engineer goal of pushing it further and further out) and a discussion of how to get to virtually any place in the known Universe. Then it hits on four pages just on the Dimensional Anomaly, how it works and how they deal with it, before turning to a discussion of specific places, like the Cop (both old and new), Darkside, and the Void Engineer views of the Shard and Shade Realms. But after that, it hits the big deal: Threat Null. First mentioned in the Syndicate book and alluded to constantly throughout this one as a dire threat that they can't tell the rest of the Union the details of, we find out why at the end of Chapter 3. Threat Null is the Technocratic Union, or at least, the descendants of it that were lost in the Anomaly. Now, mutated and changed by the Void, they've become a sort of metastasized version of themselves, and when they meet Processed Technocrats, they speak with the voice of Control. The biggest mystery left completely unresolved with them, though, is why there are no apparent Void Engineers in Null. Null is probably the most innovative antagonist added to Mage since near the beginning, and I look forward to seeing how it develops as the line comes back to life.
Chapter 4 is back to the Convention book routine, by and large: notable engineers, some legends (which include the narrator of the history in the 1st Edition Void Engineers book, now a known Nephandus) and more information on Station Yemaja which was mentioned several times in Progenitors Revised. Then general advice for STing for Void Engineers and a Voidship crew. Dimensional Science and Void Correspondence are fairly straightforward alternate approaches to spheres. The best thing in this section, though, are the Voidcraft rules. How to build them, how much they cost, what spheres are required, and how Voidcraft Combat works, along with several examples, including the X160 Qui La Machinae, which costs roughly $7.8 billion to build. This high price explains why the Technocracy doesn't have an absolutely massive fleet, and sets up great possibilities for Void Engineer salvage operations: why build a new $7.8 billion ship when you can try to find an old one (if you have a lead) and can fit it up and upgrade it for much less?
Overall, an excellent book and an excellent end to the Revised line as M20 got off the ground. Hopefully, some of these threads will be explored further (M20 mentioned them, but Technocracy: Reloaded could do something, and hopefully if and when it happens, there's M5).