Abstract: An improved two step (dual stage catalysis) aqueous hydrogenation process and a novel trimetallic hydrogenation catalysts consisting essentially of highly dispersed, reduced ruthenium and rhenium metals in the presence of a third metal tin on carbon support particular useful in the second stage of the process. Such process and catalyst exhibit high conversion rates in aqueous solution hydrogenation of hydrogenatable precursors (e.g., maleic acid, succinic acid, corresponding esters, .gamma.-butyrolactone, etc.) to tetrahydrofuran, .gamma.-butyrolactone, 1,4-butanediol and mixtures thereof wherein the relative molar ratio of 1,4-butanediol to tetrahydrofuran products being produced can be controlled.