Abstract: Endothermic reactions (those whose heat of reaction is positive) may be controlled in a truly isothermal fashion with external heat input applied directly to the solid catalyst surface itself and not by an indirect means external to the actual catalytic material. This heat source can be supplied uniformly and isothermally to the catalyst active sites solely by conduction using electrical resistance heating of the catalytic material itself or by an electrical resistance heating element with the active catalytic material coating directly on the surface. By employing only conduction as the mode of heat transfer to the catalytic sites, the non-uniform modes of radiation and convection are avoided permitting a uniform isothermal chemical reaction to take place.