In this paper we present the first study of the role of double K-shell-to-K-shell electron transfer in heavy-ion--atom collisions. Consistent analysis procedures for obtaining total cross sections for both single and double K-shell-to-K-shell electron transfer are outlined based on the charge-state dependence of the total x-ray-production cross sections for K-shell satellite and hypersatellite x rays, respectively. Theoretical calculations for the single and double electron-transfer cross sections based on the two-state atomic expansion model and the independent-electron approximation are presented and are found to be in excellent agreement with experiment.