Hex is not a book but rather a recurring device in the Discworld series, mostly in later books centered on wizards - basically a technomagical computer analogue

Hex is not a book but rather a recurring device in the Discworld series, mostly in later books centered on wizards - basically a technomagical computer analogue that is powered apparently by ants rather than electrons. Not sure how much did the late Pterry have the hivemind=computer analogy in mind but as an added bonus on the surface it does open up at least a few jokes about computer "bugs".