What do we know about granites? That was, in essence, the unifying thread of the 2nd Hutton Symposium on Granites and Related Rocks (or “Hutton Down Under”), held in Canberra, Australia, September 23–28, 1991. Questions considered, and often hotly debated, included how are granitic plutons emplaced?, what is the mechanism of differentiation?, is the mantle a possible source for granitic magmas?, and how closely do granite compositions reflect sources compositions, or are there important anatectic or differentiation modifications?