Epigenetics links genetics to the environment and disease, revealing how environmental factors and genetic variations influence biological processes. This review discusses the evolution of epigenetic research, emphasizing its role in cellular identity, memory, and plasticity. Epigenetic mechanisms, such as DNA methylation, histone modifications, and non-coding RNAs, regulate gene expression and chromatin structure, enabling the inheritance of alternative gene activity states without DNA sequence changes. These mechanisms are crucial for development, disease, and evolution, and their study has expanded to include transgenerational and intergenerational inheritance, as well as the effects of the environment on genome integrity. Epigenetic inheritance involves the transmission of chromatin states across cell divisions and generations, often through stable chromatin structures and regulatory proteins like Polycomb and Trithorax complexes. These systems maintain gene expression patterns, preventing accidental reprogramming and ensuring developmental and physiological homeostasis. However, epigenetic changes can lead to disease when they disrupt normal gene regulation. The field has also explored how environmental factors, such as diet, temperature, and chemical exposure, can influence epigenetic states, potentially affecting health outcomes across generations. Recent advances in epigenetics include the use of single-cell and high-throughput technologies to study epigenetic inheritance in detail, revealing how chromatin organization and 3D genome architecture contribute to heritable states. These findings highlight the importance of epigenetic mechanisms in human health, offering potential therapeutic targets for diseases such as cancer and neurological disorders. The study of epigenetic changes in aging and disease has also revealed how environmental and genetic factors interact to influence lifespan and healthspan. As the field continues to evolve, understanding the complex interplay between epigenetics, the environment, and genetics will be crucial for developing new strategies to improve human health and treat diseases.Epigenetics links genetics to the environment and disease, revealing how environmental factors and genetic variations influence biological processes. This review discusses the evolution of epigenetic research, emphasizing its role in cellular identity, memory, and plasticity. Epigenetic mechanisms, such as DNA methylation, histone modifications, and non-coding RNAs, regulate gene expression and chromatin structure, enabling the inheritance of alternative gene activity states without DNA sequence changes. These mechanisms are crucial for development, disease, and evolution, and their study has expanded to include transgenerational and intergenerational inheritance, as well as the effects of the environment on genome integrity. Epigenetic inheritance involves the transmission of chromatin states across cell divisions and generations, often through stable chromatin structures and regulatory proteins like Polycomb and Trithorax complexes. These systems maintain gene expression patterns, preventing accidental reprogramming and ensuring developmental and physiological homeostasis. However, epigenetic changes can lead to disease when they disrupt normal gene regulation. The field has also explored how environmental factors, such as diet, temperature, and chemical exposure, can influence epigenetic states, potentially affecting health outcomes across generations. Recent advances in epigenetics include the use of single-cell and high-throughput technologies to study epigenetic inheritance in detail, revealing how chromatin organization and 3D genome architecture contribute to heritable states. These findings highlight the importance of epigenetic mechanisms in human health, offering potential therapeutic targets for diseases such as cancer and neurological disorders. The study of epigenetic changes in aging and disease has also revealed how environmental and genetic factors interact to influence lifespan and healthspan. As the field continues to evolve, understanding the complex interplay between epigenetics, the environment, and genetics will be crucial for developing new strategies to improve human health and treat diseases.