This book comprehensively discusses topics like biology and diseases related to the field of stem cells. Stem cells play an important role in our normal life as well as in the pathogenesis of disorders. Currently, these cells are clinically applicable in hematopoietic stem cell transplantation. However, a lot of work is still needed for expanding the application of these cells in many other disorders. For a secure and efficient application of these cells, better knowledge of their biology, their interaction with other cells (especially supporting niche cells), maturation, growth as well as their immigration in both normal and abnormal conditions is required. For the purpose of clinical applications too, better understanding of their safe manipulation and separation techniques is required. This book aims at clarifying a few major aspects of stem cell biology, their characteristics, assessment of damage to cells during ex-vivo manipulation as well as their role in a model of cancers (chronic myeloid leukemia).