Abstract: Moisture content measurements are accomplished as a function of temperature by measuring the temperature-difference versus natural-logarithm-of-heating-time response of a sample of a predetermined material during a predetermined interval of application of a predetermined quantity of heat, determining the slope of that response at a portion thereof of substantially maximum slope, determining the mean sample temperature through the duration of that response portion, and calculating the moisture content of the sample as a function of that slope and that mean temperature. A thermal probe is used for both applying controlled heat to a material sample and sensing resulting temperature changes within the sample. The probe includes a line heat source and either a thermocouple sensing element or a thermistor sensing element. Sample holders are employed which limit diversion of heat from the heater via paths other than through the sample material.