The Marcellus Shale – a vast rock formation that holds a huge reservoir of natural gas – is at the center of one of the most controversial natural resources issues of our time. This is primarily because of the unconventional method used to extract gas from the shale – slickwater horizontal high-volume hydraulic fracturing, or hydrofracking. Concerns about how widespread use of the practice will affect the natural environment – most especially freshwaters at the local level and climate at the global level – have thrust geology into the public view in a way seldom otherwise experienced. The Science Beneath the Surface reviews the major science and technology issues around this complex topic, offering impartial, evidence-based, thought-provoking information to help citizens decide what to do.