Georgius Agricola's De Re Metallica of 1556 is the first professional account of the mining industry and is largely derived from first hand accounts of practice in Europe. In visual terms, it is richly interpretive of the many processes, but delightful in its several ways of depicting what is unseen from above the surface, and restricted beneath the Earth's surface. Other images are equally inventive, the clearest diagram ever (foot of screen) and the viewer immersed in surveying.