This chapter reports some fundamental thermodynamic and kinetic aspects of the high-energy ball milling (HEBM) technique. HEBM technology consists in exposing definite quantities of powders to the repeated action of hitting balls, opportunely launched by a BM device. The increased interest in HEBM as an ecofriendly alternative process able to synthesize complex chemical products has led to an increased number of experiments conducted in presence of small portions of a liquid phase. The chapter presents some experimental results obtained by different BM techniques that were used for the synthesis and/or the processing of various materials of interest in the field of environmental and energy applications including nanoparticles, microporous materials, and nanocomposites. Two strategies are commonly employed for producing nanomaterials: top-down and bottom-up processes. The chapter also provides some examples of materials developed using ball milling (BM). © 2015 Wiley-VCH Verlag GmbH & Co. KGaA. All rights reserved.