The Line of Polity (TLoP) is the second novel in the author's Agent Cormac series, the first (Gridlinked) being reviewed here in February 2012. A couple of extracts from that review in the way of introduction:
The novel starts in the twenty-fifth century when humanity has spread to many worlds using FTL ships, but has since installed interstellar matter-transmitters known as runcibles for routine travel. This empire (known as the Polity) is managed not by people but by Artificial Intelligences which vastly exceed human capabilities. They are linked via the AI Grid, to which some humans also have direct mind links surgically implanted in their brains. The Polity's interests are defended by the ECS (Earth Central Security) which sends agents wherever trouble arises. Their top agent is Ian Cormac, who has been gridlinked for thirty years - ten years longer than the recommended maximum.
The story has many familiar SF elements: modified human types (including outlinkers who are specialised for life in zero-gravity space stations); artificial humans (golems) who are much faster and stronger than any human; physically boosted soldiers (sparkind); anti-gravity machines, anti-matter bombs and proton beam weapons. This is all combined into a page-turning thriller which maintains a brisk pace despite being over 500 pages long. It is quite a traditional story, filled with the basic optimism of a galaxy-wide humanity, but is none the worse for that.
It is not essential to have read Gridlinked first but it is helpful as TLoP features several of the same characters as well as the same background (which is explained more thoroughly in Gridlinked), and there are various references to the characters' shared history.
TLoP begins in the currently fashionable way by starting several separate plot threads running, in various locations and with different characters, that initially have no obvious connection but which gradually merge, mostly towards the end of the story (one of them isn't explained until right at the end). The main focus is the planet Masada, run by a ruthless, absolutist theocracy living in luxurious orbiting satellites while human slaves are used as farm labourers on the planet's surface, whose atmosphere holds insufficient oxygen to support human life (symbiotic creatures are attached to the labourers to provide them with sufficient oxygen in their blood). Masada is just outside the boundary-line of the Polity, but there are plans afoot to support a rebellion to overthrow the theocracy.
The beginning is set on Masada as we follow a young female slave, Eldene, in her dangerous task of harvesting the valuable squerms, fierce creatures whose flesh is a delicacy throughout human space. We next meet Apis, a young Outlinker whose space station is being attacked by a type of fungus; and all this is still in the Prologue. In the main body of the novel we soon meet Skellor, a rogue genius inventor who has acquired some technology from the long-dead Jain alien civilisation; Aberil and Loman Dorth, rulers of the theocracy; Lellan Stanton, leader of the (literally) Underground resistance on Masada; plus some characters familiar from Gridlinked: the mercenary Ian Stanton (Lellan's brother) and his partner Jarvellis; Mika the scientist; the ECS agents Thorn and Cormac; and last but not least, the vast alien being called the Dragon and its creations, the dracomen.
What follows is a complex series of increasingly interrelated plots as Eldene makes her bid for freedom with the aid of the enigmatic fellow-slave Fethan, the theocracy perfects its devastating orbital weapon designed to penetrate to the deep caves of the Underground, Skellor tests the transformative power of the Jain device, Ian Stanton and his sister work to free Masada while the theocracy is tightening its grip, and Cormac is in the middle of the whirlwind, attempting to deal with the Dragon which (as usual) has its own agenda.
This book is even longer than its predecessor at 650 pages but the story rattles along at a good pace. Despite the number of characters and the constantly switching viewpoints it is not too difficult to keep up with who's who and doing what to whom. There is the odd eyebrow-raising element which (as is so often the case) is not concerned with the big story elements but some of the incidental details. The one which struck me most here was the presence of theatrically extreme predators on Masada, orders of magnitude bigger than their prey. A cursory glance at the history of life on Earth indicates that the top land predators (lions, wolves, even T. Rex) are generally smaller than their prey – really big predators have been rare and tend to die out as soon as conditions for them become less than optimal, because they have to eat so much just to stay alive – and no explanation is provided about why Masada should be so different.
Despite this niggle I enjoyed TLoP and will acquire the three remaining novels featuring Ian Cormac: Brass Man, Polity Agent and Line War.