Absolute favorite is Arturo Perez-Reverte. Try The Club Dumas or The Seville Communion.
For sci-fi, it's either Bruce Sterling or Jonathan Letham.
Historical: anything by George MacDonald Frasier! Alan Furst is good for the WWII period.
Try Ray Kurzweil's Age of Spiritual Machines...a great read
"War is an ugly thing but not the ugliest of things; the decayed and degraded state of moral and patriotic feelings which thinks that nothing is worth war is much worse. A man who has nothing for which he is willing to fight, nothing which is more important than his own personal safety, is a miserable creature and has no chance of being free unless made and kept so by the exertions of better men than himself."
John Stuart Mill