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FOUCAULT’S PENDULUM BY UMBERTO ECO (1988) the first 100 pages are a hard initiation, but persevere for an audacious rewriting of occult history and a terrifying paranoid thriller.
MASK OF THE OTHER BY GREG STOLZE (2011) troops discover an eldritch relic during the first gulf War, and set themselves up as occult soldiers of fortune. Mixes mysteries, military and the Cthulhu Mythos with aplomb.