We have developed a computer-assisted electrothermography method to determine the intrinsic kinetics of reactions under conditions similar to those realized during combustion synthesis of materials. In this method, metal wires are heated in a reactive gas atmosphere in a controlled manner by passing electric current, and when time-dependence characteristics of electric power applied to the wire are measured, the reaction kinetics can be extracted. To illustrate the technique, it is applied to investigate the kinetics and other features associated with the reaction of titanium with nitrogen at 1 atm of pressure. The temperature range 1400-2300 K and heating rates 10(4)-10(5) K/s are studied. It is shown that at temperatures below the melting point of titanium, the reaction follows a parabolic rate law, corresponding to a sharp-interface model with nitrogen diffusion through the developing titanium nitride layer as the rate-controlling step. The obtained activation energy value (230 kJ/mol) is in good agreement with this model. At higher temperatures, however, the reaction mechanism is different because of faster diffusion of nitrogen in molten titanium. In addition, the reaction rate is shown to depend strongly on the heating rate and on the heat pretreatment of titanium.