Non fiction, Presuasion by Robert Cialdini. I'm fascinated by psychology and as technical staff we should try and develop skills beyond the technical. This shows you how to set a scene to achieve your aims. Sadly I'm still rubbish at being a Machiavelli and just try and work hard and effectively and hope that gets me where I want to be. Well, at least I kind of understand there ARE other undercurrents.
Fiction, Hyperion (four book series) by Dan Simmons. Science fiction rooted in literature. I won't lie, it's tough going in places, but worth persevering if you want a bit more than the standard fantasy tropes. Interesting ideas that overreach sometimes, but are always fascinating, especially the stuff on AI.