Maps has a double meaning in this book. A map means both what we think of when we hear the word (i.e. a top-down view of some topography) and a meaning that is more in line with biological thinking. A map, in this book, can also mean a 'life map'. The latter sense of map (i.e. life-map) is the more important sense of the word 'map' in War of the Maps.
The book is about biological warfare on a hypothetical planet constructed out of a Dyson sphere. We are given to know this information in the Acknowledgments, where the paper 'Dyson Spheres Around White Dwarves' is cited as the novum for the novel we are reading. As with McAuley's previous book, Austral, we are riding on the shoulder, in third person limited mode, of the protagonist, in this case 'the lucidor' (who also has a name, used only once or twice in the book).
Despite being, technically, 'hard' or extrapolative SF due to the central novum's leveraging of biological theories of 'mapping' (i.e. DNA manipulation), when you are actually reading the book it feels much more like fantasy. We know that science fiction and fantasy exist on a continuum, and it is one of the many innovative features of this book, one of the things it does uniquely well, to put us on that continuum and slide evenly along it, from the 'harder' biological side, on over to the 'softer' fantastical elements involving 'shatterlings', mind-reading, magic, and other-worldly beings.
The other-wordly beings and godlings play a major role in shaping the plot, whose entire resolution revolves around being able to locate the site of one of those fallen-from-the-sky. Various networks (again, we are into 'hard' territory here because there is a materiality to how the various beings communicate that relies upon a realistic notion of how the networks function) link the different more-than-human actors, actants, and mediators that inhabit the various territories, islands, continents, and enclaves battling for the spaces of this mirror-lighted 'globe.' One page 27 we see that,
"a huge latticework globe stood on a plinth of black baserock. Maps, some entire and others patchworked from islands or continents, none bigger than a child's hand, were scattered thinly across the surface. The home map, Gea, was a squarish red tile close to the equator, smaller than most of the rest, and a silvery ball representing the Heartsun was spindled at the centre, and everything was spattered by the droppings of a fractious parliament of vivid green birds which had colonised the globe's pole, chattering each to each and scolding passers-by."
The islands/continents that make up this world are themselves called maps, and they are also territories and as such, are peopled and cultured, here into wars with each other. This is a comment on human territoriality as much as it is upon the dangers of the manipulations of our biological 'maps'. We are, indeed, reading through a speculation on the philosophical and social implications of such manipulations upon our own worlds, made literal through the use of fantastical titles and trainings attained by the protagonists. Many are philosophical practitioners and, as such, are given great respect on the fantastical world, where in our, real, world they would have none.
Philosophical speculation abounds with being obvious about it. A less subtle reading would miss this point, but this book could appeal nonetheless, I think, to the less self-aware reader interested only in action-stories and fighting. We do get a lot of scenes of hand-to-hand combat with staves and spells and the like, and aid often comes from quasi-mystical beings and godlings. So we can get our fantasy fix too.
If you liked Fairyland a lot, then this book is for you, because it is in much the same vein. If you've only read Austral before because you liked its straightforward extrapolation of a climate change scenario focused on Antarctica, then the fantastic side here might appeal less. I, for one, love both Fairyland and Austral, and therefore, I doubly loved War of the Maps. It is the top book of the year 2020 for me so far.
