A methodology is presented for elucidating the functional features of the intrinsic kinetic expression from an analysis of the multiplicity features of isothermal experiments. The analysis makes use of the sensitive dependence of the multiplicity features on the form of the rate expression and the presence of inter- and/or intraparticle transport limitations. Simple criteria and graphical tests are developed for the analysis of experimental diagrams of rate vs. limiting reactant concentrations. Three classes of kinetic models are shown to be capable of accounting for the observation of multivalued dependence of the rate on the limiting reactant concentration. The methodology is illustrated by analyzing several published isothermal multiplicity data and developing kinetic models which describe the observed features.