Whether the world's best truffles come from Piedmont or P rigord inspires impassioned debate, but the effects of dwindling supply and insatiable demand for the elusive mushroom are unquestionable: prices through the roof, intrigue and deception, and ever more intensive efforts to cultivate. As international mycologist Ian Hall and his colleagues have written, "Attempts at taming the truffle, of ordering its growth and harvest, now span the globe,...