The Traders’ War, by Charles Stross

Second paragraph of third chapter:

Sometimes, when he was extremely tired, he’d lose his sense of smell. It was as if the part of his brain that dealt with scents and stinks and stuff gave up trying to make sense of the world and went to sleep without him. At other times it would come back extra strong, and any passing scent might dredge up a slew of distracting memories. It was a weird kind of borderline synaesthesia, and it reminded him uncomfortably of a time a couple of years ago when he’d been on assignment in some scummy mosquito-ridden swamp down in Florida. The hippie asshole he was staking out had made the tail, and instead of doing the usual number with a Mac-10 or running, had spiked his drink with acid. He’d spent a quarter of an hour in the bathroom of his hotel room staring at the amazing colors in the handle of his toothbrush, marveling at the texture of his spearmint dental gel, until he’d thrown up. And now he was so tired it was all coming back to him in unwelcome hallucinatory detail.

Compilation of the third and fourth volumes of the Merchant Princes series, in which our protagonist and her ex-boyfriend are entangled in dynastic feuds in a family who have the ability to walk between parallel universes; our own, and two others, one more feudal, one more eighteenth-century, the action in all cases set in what we call the northeastern USA, most of whose population are descended from settlers across the ocean. The first compilation volume was The Bloodline Feud.

Stross’s heroine makes an early mistake here, trying to bring her know-how from our world to gain power and status in the feudal society of her origin, but over-reaching and then having to deal with the consequences of dynastic displeasure, while the dance of intelligence services around one another between the worlds gets steadily more intricate and nasty. The pace continues to be intense and well constructed. Great stuff. You can get it here.

(By odd coincidence, the day I finished reading this, I later bumped into the author in the bar in Chicago and had a long chat.)

This was my top unread book acquired in 2017. Next on that pile is the next in this series, The Revolution Trade.