Stem Cell Biology is a foundational field in regenerative medicine focused on understanding the properties, mechanisms, and therapeutic potential of stem cells. It explores the biology of embryonic stem cells, adult stem cells, and induced pluripotent stem cells (iPSCs), with emphasis on self-renewal, differentiation, and cellular plasticity. Research in this domain provides insights into tissue development, homeostasis, and repair, forming the basis for novel treatments across various medical disciplines. Key areas include stem cell signaling pathways, epigenetic regulation, lineage specification, and cellular reprogramming. Stem cell biology also underpins advancements in disease modeling, drug screening, and personalized medicine. Ethical considerations, scalability, and safety remain central to ongoing investigations. This field plays a critical role in developing cell-based therapies for neurodegenerative disorders, cardiovascular diseases, diabetes, and organ regeneration.