There’s a question that’s been bothering me for some time. Many flint human artefacts show evidence of retouching to the edges, apparently either to blunt them, to make them easier to hold, or to sharpen them. But why exactly would anyone want to sharpen the edge of a flint flake or blade? If you strike a flake or blade from a core, you get an object which usually has a continuous edge that is – literally – sharper than a razor. Flint can take an edge that it only a few molecules thick, far thinner and sharper than the finest steel, which is why flint is still used today by some surgeons for their scalpels. So why mess up a near perfect cutting edge by retouching it with an antler tine or bone point? I can understand if the aim is to make a denticulate saw-blade for cutting through wood, but not for the vast majority of flint tools – knives, scrapers, axes, adzes and the like. Has anyone done any comparative trial experimentally on this issue?