I was pretty sure that were a few MacInnes titles that I hadn't read - the difficulty is that I read the bulk of her work so long ago that I can't be sure, unless it's a book that I've reread in the last few years.
I had convinced myself that I had read this one - the setting in Greece seemed like something that I would've read, given how appealing I find it. Now that I've finished it, I'm pretty sure that this was my first read.
Decision at Delphi is classic MacInnes - the stoically handsome and intensely capable man with a long-past military background who becomes embroiled in a modern plot by extremists to precipitate another conflict, the attractive young woman who is his love interest, who needs protecting but who is also generally brave and capable in her own right, and the Nazis, Communists, Fascists or various other extremists who need thwarting.
MacInnes is equal opportunity with her opprobrium, and I always admire the way that she doesn't pick a preference between extremists on the right and extremists on the left, making the valid point that if you go far enough to either end of the political spectrum, you meet in monstrosity.
Older espionage books are paced so differently from modern thrillers that they can seem to drag even when the author is carefully building characters and backstory. Decision at Delphi did have that effect on me - the pacing seemed quite slow until I reached the 75% mark, at which point the stakes were increased and the tension really ratcheted into high gear. Nonetheless, as is always the case with MacInnes, I enjoyed this piece of spy fiction and would give it high marks for the mechanics of the plot and the likeability of the characters. In addition, the relationship between Kenneth Strang and Cecilia Hillard felt more modern and equal than many of her relationships, which can feel very regressive and gendered.