This volume describes the latest findings on transcriptional and translational regulation of stem cells. Both transcriptional activators and repressors have been shown to be crucial for the maintenance of the stem cell state. A key element of stem cell maintenance is repression of differentiation factors or developmental genes - achieved transcriptionally, epigenetically by the Polycomb complex, and post-transcriptionally by RNA-binding proteins and microRNAs. This volume takes two approaches to this topic - (1) illustrating the general principles outlined above through a series of different stem cell examples - embryonic, iPS and adult stem cells, and (2) describing several molecular families that have been shown to have roles in regulation of multiple stem cell populations.