The article by John H. Luft discusses improvements in epoxy resin embedding methods for electron microscopy. The author outlines modifications to the original methods developed by Glauert and Kushida, which have been shown to yield rapid, reproducible, and convenient embedding techniques. These methods offer several advantages over methacrylate embedding, including less tissue damage, better preservation of cellular fine structures, and reduced degradation during electron beam irradiation. The author highlights the challenges encountered with traditional epoxy resins, such as inadequate penetration and difficulties in cutting, which have led to the development of alternative methods using different epoxy resins. Two approaches are detailed: one based on aromatic Araldite resins and another on aliphatic Epon 812. Both methods have been successfully implemented in the author's laboratory and have been shared with other institutions for their use. Key improvements include the use of propylene oxide to enhance penetration, a three-stage curing process to reduce cross-linking, and the selection of appropriate curing temperatures and resin proportions to improve cutting quality. The methods allow for rapid embedding, easy sectioning, good contrast in electron microscopy, and a wide range of hardness options. The article concludes with a summary of the advantages of the new methods and acknowledges the contributions of various individuals and institutions in the development and evaluation of these techniques.The article by John H. Luft discusses improvements in epoxy resin embedding methods for electron microscopy. The author outlines modifications to the original methods developed by Glauert and Kushida, which have been shown to yield rapid, reproducible, and convenient embedding techniques. These methods offer several advantages over methacrylate embedding, including less tissue damage, better preservation of cellular fine structures, and reduced degradation during electron beam irradiation. The author highlights the challenges encountered with traditional epoxy resins, such as inadequate penetration and difficulties in cutting, which have led to the development of alternative methods using different epoxy resins. Two approaches are detailed: one based on aromatic Araldite resins and another on aliphatic Epon 812. Both methods have been successfully implemented in the author's laboratory and have been shared with other institutions for their use. Key improvements include the use of propylene oxide to enhance penetration, a three-stage curing process to reduce cross-linking, and the selection of appropriate curing temperatures and resin proportions to improve cutting quality. The methods allow for rapid embedding, easy sectioning, good contrast in electron microscopy, and a wide range of hardness options. The article concludes with a summary of the advantages of the new methods and acknowledges the contributions of various individuals and institutions in the development and evaluation of these techniques.