The first aerogels were prepared in 1931 by Steven S. Kistler of the College of the Pacific in Stockton, California. Kistler was trying to prove that a gel contains a continuous solid network of the same size and shape as the wet gel. Kistler observed that a wet gel, if allowed to dry on its own, would shrink and become severely cracked. He correctly surmised that the solid component of the gel was microporous, and that the pore structure collapsed due to the liquid-vapor surface tension forces of the evaporating liquid. Kistler noted that in order to produce an aerogel, it would be necessary to replace the liquid of a wet gel with air by some means in which the surface of the liquid does not recede within the gel. The gels studied by Kistler were silica gels prepared by the acidic condensation of aqueous sodium silicate. Kistler succeeded...