Porous carbon (activated carbon or charcoal) has been known for over 3,000 years and is regarded as the most versatile porous material, not only because of the wide variety of structures that carbon offers, but also because of the sheer variety of applications, ranging from gas storage to molecular sieves, catalyst supports, absorbents, electrodes in batteries, supercapacitors, and capacitive desalination. The performance of all of these technologies depends heavily on pore size, and, until the recent arrival of Tunable Nanoporous Carbon, no manufacturing methods were able to provide the control of the pore size. Starting with an inorganic precursor, such as silicon carbide, materials scientists at Y-Carbon, Inc., King of Prussia, Pa., and Drexel Univ., Philadelphia, Pa., etched the metal or metalloid from the carbide in a halogen environment, such as chlorine, at elevated temperature. In this process, as metal is extracted layer-by-layer from the rigid metal carbide lattice, atomic-level control of porosity is possible. As pore formation in this process is due to removal of metal as a gaseous metal chloride, the carbon material contains open and accessible pores. The transformation of metal carbide to carbon is conformal and, because of conservation of shape and size in this process, carbon atoms are slightly relocated from their original positions during treatment, creating a porous carbon network. The development has shown that pore size control can be achieved with sub-angstrom (0.5 to 2.2 nm range) and sub-nanometer (3 to 30 nm range) accuracy by selecting the precursor material (titanium carbide, silicon carbide, etc.) and the synthesis conditions (temperature, time, etc.).