This is a self-contained exploration of the theoretical background of one of the most widespread activities in hydrocarbon wells, that of hydraulic fracturing. The authors provide readers with comprehensive treatment of the basic phenomena, including: linear elasticity, stresses, fracture geometry and rheology. The diverse concepts of mechanics are integrated into a coherent description of hydraulic fracture propagation and each of the chapters in the book are cross-referenced continuously with emphasis on connections between the various phenomena and numerous numerical examples.