It is, as hinted above, brilliant. Parker's infectious, stylish use of language combines with a distinctly philosophical approach to make one of the best series I've ever read.
The Engineer Trilogy is about a lot of things, and a lot of people, but, central to the action is Ziani Vaatzes. Vaatzes is an engineer from the Republic of Mezentia, a sort of Roman analogue that has a distinct technological advantage over its surrounding nations. Vaatzes is an impressive engineer at that - so when he's sentenced to death for a seemingly minor infraction of Mezentine law - his analytical mind clicks into action. Not only does Vaatzes escape from prison, but, once in exile, begins a series of military and political maneuvers will change the face of the world.
This is well beyond your typical stableboy/prophecy stuff, and, despite the importance of technology, this shouldn't be confused with steampunk either. Parker is past world-building or fantastical gimmickry.
The setting is an abstracted analogue of the real world and the cultures are deliberately streamlined archetypes. The characters are brilliant - empathetic, fascinating and absorbing - but even they're not the core of the book. This series is a deliberately provocative exploration of what makes people tick.