This book describes transcription factors in the context of hematopoietic development and reveal mechanistic insights how they orchestrate specific gene expression patterns. Several examples from lymphoid and myeloid lineages are given as well as particular examples of leukemia fusion proteins that contain a part of a transcription factor. In the given chapters covering each one particular example, the function of transcription factors is characterized in normal as well as leukemic contexts. New technologies such as ChIP-Seq or RNA-Seq, that make use of genome-wide sequencing, have shown that such master regulators of blood cell development often work in combinatorial fashion and, when dysregulated, results in leukemogenesis. This book is not only intended for experts but it should also be a useful resource for younger scientists or scientists from other disciplines, who may use this book as a stimulating starting point for further discoveries and/ or translational endeavors.