This thesis focuses on the history of embryonic stem cell research, spanning in particular the nineteenth and twentieth centuries. As yet, there has not been a comprehensive history of embryonic stem cell research carried out, which is a particular aim of this thesis. The first two chapters consider the conceptualisation of the stem cell, and the development and diversity of relevant disciplines and their establishment in the twentieth century; in particular, this covers heredity, genetics,embryology and development. This is illustrated through the use of experimental embryology, or 'fantastical experiments', that were proposed in the nineteenth century, and carried out in the twentieth. The third chapter considers the theoretical and practical links between cancer and embryonic cells. The fourth and fifth chapters explore the isolation and culture of murine and human embryonic stem cells, focusing on the social, political, and economic factors affecting stem cell research, and the motivations behind the isolation of embryonic stem cells in the 1980s and 1990s. The sixth chapter queries whether the history presented suggests that a new stem cell concept is emerging. There are three questions that this thesis aims to answer. Firstly, what are the (historical) social and political influences that affect (embryonic) stem cell research? Evidence presented suggests that this has occurred from the nineteenth century, and continues today. Secondly, this thesis queries the importance of cell fate, and cell fate studies, to embryonic stem cell research. Since one of the two abilities of stem cells is the ability to differentiate, cell fate and studies of cell fate are central to developing a stem cell concept, and may also be influential in changing that concept in the future. Lastly, this thesis asks which paradigms have affected embryonic stem cell research throughout its history. In particular, the genetic paradigm is shown to be influential from the early twentieth century onwards. More recently, it has been proposed that stem cell research needs to undergo a paradigm shift, from the stem cell entity view, to the stem cell state view. This is also explored through the thesis, with the aim of generating a better understanding of stem cells for future researchers.