A unifying theory for the molecular biomechanics ofreceptor-ligand interaction is being developed, which is basedon the probabilistic formulation for kinetics of small systemsplus the constitutive laws describing the dependence ofkinetic rates on force. A diverse set of experiments wereperformed to test the theory, including those using variouscells and molecules, being conducted under both steady andtransient conditions, and employing differmt techniquesincluding centrifugation, micropipette, and rosetting.Specific solutions to each experiment were obtained, many ofwhich are analytical. The satisfactory comparisons betweenpredictions and data not only validate the theory but alsoenable deerminaton of the constitutive equations and theassociated parametors.