Thermal-barrier coatings (TBCs) are essential for improving the efficiency and power of gas-turbine engines used in transportation, energy, and defense sectors. These coatings, typically made of 7 wt% Y2O3-stabilized ZrO2 (7YSZ) ceramics, provide thermal insulation to metallic parts in the hottest sections of the engines, enabling them to operate at significantly higher temperatures. The development of TBCs involves complex, multi-layer systems that must withstand extreme conditions, including high temperatures, thermal gradients, and mechanical stresses. The articles in this issue of *MRS Bulletin* cover various aspects of TBCs, including their processing, testing, and evaluation, as well as the challenges and opportunities in materials research. Key topics include the deposition methods for ceramic topcoats, the failure modes and testing techniques for TBCs, the role of bond-coat alloys, and the mitigation of molten silicate deposits (CMAS) attack. The overall goal is to enhance the reliability and performance of TBCs at even higher temperatures, which is crucial for meeting the growing demands of energy and transportation sectors.Thermal-barrier coatings (TBCs) are essential for improving the efficiency and power of gas-turbine engines used in transportation, energy, and defense sectors. These coatings, typically made of 7 wt% Y2O3-stabilized ZrO2 (7YSZ) ceramics, provide thermal insulation to metallic parts in the hottest sections of the engines, enabling them to operate at significantly higher temperatures. The development of TBCs involves complex, multi-layer systems that must withstand extreme conditions, including high temperatures, thermal gradients, and mechanical stresses. The articles in this issue of *MRS Bulletin* cover various aspects of TBCs, including their processing, testing, and evaluation, as well as the challenges and opportunities in materials research. Key topics include the deposition methods for ceramic topcoats, the failure modes and testing techniques for TBCs, the role of bond-coat alloys, and the mitigation of molten silicate deposits (CMAS) attack. The overall goal is to enhance the reliability and performance of TBCs at even higher temperatures, which is crucial for meeting the growing demands of energy and transportation sectors.