Stem cells are the building blocks of the body. They can develop into any of the cell types that make up our bodies. During development, they contribute to the formation of the tissues. In the adult, they contribute to homeostasis of the tissues and regeneration after injury. Stem cells carry a lot of hope for the treatment of a broad range of diseases and injuries, spanning from neurological diseases and injuries, like Alzheimer's disease, Parkinson's disease and spinal cord injuries, to diabetes, genetic diseases, graft-versus-host diseases, eye, heart and liver diseases, inflammatory and autoimmune disorders, and cancers. Stem cell research is therefore as important for our understanding of development, physio- and pathology of the body, as for therapy. 'Stem Cells' aims at providing an overview and in depth analysis of recent developments in stem cell research and therapy. It is composed of recently published review articles that encompass the field of stem cell research and regenerative medicine. All the articles went through peer-review process.