The present invention is a method for ranking the affinity of each of a multiplicity of different molecules for a target molecule which is capable of denaturing due to a thermal change. The method comprises contacting the target molecule with one molecule of the multiplicity of different molecules in each of a multiplicity of containers, simultaneously heating the multiplicity of containers, measuring in each of the containers a physical change associated with the thermal denaturation of the target molecule resulting from the heating in each of the containers, generating a thermal denaturation curve for the target molecule as a function of temperature for each of the containers and determining a midpoint temperature (Tm) therefrom, comparing the Tm of each of the thermal denaturation curves with the Tm of a thermal denaturation curve obtained for the target molecule in the absence of any of the molecules in the multiplicity of different molecules, and ranking the affinities of the multiplicity of different molecules according the change in Tm of each of the thermal denaturation curves.