For several decades, hematopoietic stem cells (HSCs) have been interesting subjects of research, due to their demonstrated therapeutic potential. HSCs were first adult stem cells to be isolated, and are routinely applied for clinical treatments of a variety of blood diseases like leukemias and autoimmune disorders. With rapid advancement in techniques for the identification, isolation, and investigation of these cells with respect to their genotypic, phenotypic, and functional capacities, there have been increasing insights on various molecular and functional features of HSCs, including the heterogeneity in their repopulation, cell proliferation, and metabolic capacities, within defined clonal populations, in steady state, and perturbed hematopoiesis. There is now extensive information on the fundamental cellular and molecular properties of HSCs, in addition to in depth investigations on exploring their clinical potential, which can provide a framework for providing insight to other emerging stem cell fields. However, isolation of HSCs yield limited number of these cells, which has always been critical in restricting a wider application of HSC-based therapies. It is necessary to explore methods for better enrichment of HSCs, and understand their biology, in order to attempt to increase either HSC numbers in vitro or their post-transplantation repopulating capacity in vivo. In this Methods Collection, we will aim to summarize the major techniques that are driving our understanding of the biology of HSCs. This curated Methods Collections will include, but will not be limited to the following topics:

1. Stem cell enrichment and heterogeneity
2. Stem cell expansion
3. Cellular and molecular characterization of HSCs
4. In vitro assays and differentiation
5. Transplantation assays and imaging engraftment
6. Genetic modification