Titanicus by Dan Abnett
My rating: 4 of 5 stars
Not a bad tale of the Adeptus Mechanicus — there aren’t too many books in the 40k universe written about them, though they’re a huge part of the lore of this literary universe (standing quite a bit higher than the Astartes in the hierarchy of how things are run in the Imperium of Man).
Titanicus deals with some of the usual things you might expect to find in a book about the Mechanicus — the politics of human-augmentation in a society that seeks species purity, the way the masses see the Mechanius as distant, aloof, etc — and some of things you would rather not see explored too far, like the relationship between the God-Emperor of man (a being exalted as a living/dead god who sits on a golden throne on the Earth) and the Omnissiah (the being who the Mechanicus are allowed to worship simply because everyone has decided to look the other way and just claim that it’s obviously another avatar of the God-Emperor).