Hans-Rudolf Wenk obtained his PhD in crystallography at the University of Zurich in 1965 and joined the Department of Geology and Geophysics (now Earth and Planetary Science) in 1967. He combined teaching with research, more recently focusing on anisotropic properties in the Earth with advanced diffraction experiments and modelling. But his career covers a wide range of topics, including several books (e.g. Electron Microscopy, 1976 with Springer; Preferred Orientation, 1985 with Academic Press; Texture Analysis, 1998,  Mineralogy, 2016, both with Cambridge University Press) and many publications. He has guided many fieldtrips introducing freshmen to California geology. Summers were often spent exploring the interesting geology of the Bergell Alps and preparing a detailed map which is used in this book. Elizabeth (Lizzy) Wenk is a plant ecologist with a PhD from UC Berkeley, investigating the distribution and physiology of alpine plants in California’s Sierra Nevada. She works at the University of New South Wales, Sydney, Australia, broadly interested in plant functional traits. She pursues a second career as a hiking guide author for California’s Sierra Nevada, having written the definitive book to the famous John Muir Trail and authoring award-winning hiking guides that cover the length of the mountain range. She has become familiar with Alpine geology at an early age on many hikes with her father. In this book her focus has been to prepare the complex multilayered digital maps that accompany every excursion.