Ion-exchange resins comprise one of the most important scientific developments of the 20th century. Their applicability to water softening, environmental remediation, wastewater treatment, hydrometallurgy, chromatography, biomolecular separations, and catalysis was recognized in numerous publications. The principle of covalently bonding ligands to cross-linked polymer networks became the basis for the area of polymer-supported reagents. The journal Industrial & Engineering Chemistry Research and its predecessors have published some of the most important papers in this field. In celebration of its 100th anniversary, this review provides a retrospective of ion-exchange resins through publications appearing in this journal.