Mechanochemistry is being heralded as a transformation for green and sustainable chemistry by allowing materials and molecules to be synthesized without need for solvent and both more quickly and in higher yields than conventional solution methods. The continued development of mechanochemistry therefore promises to revolutionize the chemical industry and help to tackle global environmental challenges. The potential applications of mechanochemistry are growing rapidly, catalyzed by the growing diversity of scientists entering the field. Therefore, it is crucial to give newcomers to the field a clear overview of the key features of mechanochemistry, many of which seemingly contradict the conventional rules of chemistry. Introduction to the Mechanochemistry of Solids provides an outline of the fundamental principles of mechanochemistry in relation to solid-state reactivity as much-needed point of introduction to the field, allowing readers to achieve a better understanding of the processes that take place in a mechanoreactor during and after mechanical action. The book tackles the following key questions: How and why can mechanical treatment help when solution chemistry fails? Why might different sample preparation be important for the outcome of mechanical treatment? Why does treatment in different devices and/or different protocols of mechanical treatment give different results? When and why does adding fluids matter? How can we know what happens in a mechanochemical reactor at the moment of treatment? Introduction to the Mechanochemistry of Solids will help expedite the further development of mechanochemistry and achieve the full potential of this transformative technology in the modern world. It is written primarily for advanced undergraduate/early graduate level students and researchers with interest in solid-state chemistry, materials science, sustainable/green chemistry, solid state physics, or applications of solid-state reactivity to industry such as the pharmaceutical and chemical sectors. It provides a much-needed resource for advanced-level courses on the mechanochemistry of solids.