The hydrocarbon resources of shale gas and tight oil have made a significant impact on North American energy reserves over the past decade. The production of so-called “unconventional” natural gas from U.S shales like the Barnett, Haynesville, Fayetteville, Marcellus, and Utica, and Canadian shales like the Muskwa, Montney, and Duvernay have saturated North American gas markets, boosted Canada's exports, and turned the U.S. into a net exporter of natural gas. Tight oil production from the Bakken Shale has made important contributions to the economy of the Canadian province of Saskatchewan. North Dakota has become the second largest oil producing state in the U.S. thanks to production from the Bakken. It trails only the state of Texas, which maintains first place because of equally prolific hydrocarbon liquids production from the Eagle Ford Shale and shales in the Permian basin. It is difficult to overstate the importance of these shale gas and oil resources to the U.S., North American, and world energy economies. North American shale development blossomed in the United States between 2005 and 2010, driven by high natural gas and oil prices, the availability of favorable lease positions on shale plays, and the application of drilling and stimulation technology that could successfully produce commercial quantities of hydrocarbons from these formations at economical costs. Development in Canada began a bit later, and some development has also taken place on shales in Mexico. Many people who express surprise at the apparent “overnight” success of shale gas and oil production were simply not paying attention. The truth is that a historic and protracted engineering struggle was required to identify, modify, and apply the right technology for economically-viable production. Modern assessments of the resource potential of these rocks began in the late 1970s, as did the first systematic engineering attempts to drill directional wells and hydraulically fracture shale. Success was elusive for nearly two decades, however, u...