Stem cells and regenerative medicine is a fast emerging field with rapid strides of progress and focus on human health. Successful utilization of stem cells in regenerative medicine depends on two important features. One, stem cells can grow and divide indefinitely, and two, stem cells can differentiate into specialized cell types that make up tissues such as pancreas, heart, liver, blood, and others. Utilizing the property of differentiation, stem cells can be engineered to produce cell types to replace wornout cells and to regenerate damaged tissue. The scope for improving healthcare using stem cell therapies is thrilling, but considerable technical challenges and methodological constraints need to be addressed. There is a great need for isolation and propagation of “transplant-ready” or “clinical-grade” stem cells and screening methods, well before they are used in therapies. Recent scientific advances have contributed enormously to the development of new methods pertaining to both embryonic and adult stem cell isolation, characterization, expansion in undifferentiated state, customized differentiation, efficient stem cell transduction for gene therapy, quick monitoring of rejection, through polymerase chain reaction approaches following transplantation, and more. The scientific progress that makes stem cell biology so exciting also threatens to suffocate researchers with an avalanche of information. Keeping with the tradition of Humana Press to bring these developments to the forefront in a timely manner, the book Stem Cell Assays aims to present scientific advances in stem cell methods for a wider use by novice and expert scientists, through the Methods in Molecular Biology series.