USE OF WEAPONS was published in 1990
It is a Culture novel, first drafted in 1974

The man known as Cheradenine Zakalwe was one of Special Circumstances’ foremost agents, changing the destiny of planets to suit the Culture through intrigue, dirty tricks or military action.
The woman known as Diziet Sma had plucked him from obscurity and pushed him towards his present eminence, but despite all their dealings she did not know him as well as she thought.
The drone known as Skaffen-Amtiskaw knew both of these people. It had once saved the woman’s life by massacring her attackers in a particularly bloody manner. It believed the man to be a burnt-out case. But not even its machine intelligence could see the horrors in his past.
Iain added, “In Sma’s introductory letter in The State of the Art, she says that she’s been off-planet with her drone for a hundred days or so. It’s during that time that the events in Use of Weapons happen. There’s also a tiny reference to The State of the Art in Use of Weapons where Sma’s about to be lifted off the planet, she gives an instruction to ‘send a stalling letter to that Petrain guy’. ‘That Petrain guy’ is actually the person to whom the novella is addressed (Parharengyisa Listach Ja’andeesih Petrain dam Kotosklo). Another nuance is that Petrain is also the scholar who wrote the essays at the end of Consider Phlebas. He forms a sort of scholarly link between the books, but he doesn’t appear in any of them.

German cover
“There’s the whole thing about concentricity in Use of Weapons, about concentric layers of defence. And at the end of the book you have someone throwing stones in a pond with these ripples coming out. The whole book is actually based on a concentric framework. I like doing that because it’s like a conceit.”