The Judas Goat by Robert B Parker
This 1978 novel features Parker's Boston private eye Spenser but it's not what I was expecting from what I've encountered previously.
I've read and enjoyed other Spenser novels but I wasn't as keen on this one. To my mind it didn't read like a private eye story so much as an international action thriller, set as it is in London and Montreal with brief stints in Copenhagen and Amsterdam, chasing a group of young terrorists. I could almost picture the film adaptation in my head as I read it, there seemed to be a lot in the way of blond moustaches, flamboyant shirts and being hard, and what with the London section it did make me think of some kind of Alistair MacLean episode of the Sweeney. It didn't help that at a distance of thirty-odd years, Spenser's friend Hawk comes across as a black American stereotype: the drawling, slick-dressing ladies' man.
I read it to the end - it's not very long, after all (about 170 pages in my Penguin edition) - but I wouldn't recommend it to fans of the private eye novel looking for a way in to Parker. If 1970s action-packed thrillers are your thing, you might have more luck with it.