Organisms have come up with many clever mechanisms for sensing and reacting to
the environment. For example, our powerful nervous system with its complex neuronal networks can sense, process and respond in a fraction of a second and cells can sense the outside world with an impressive array of surface receptors that trigger intricate phosphorylation cascades. However metazoan animals have evolved an additional form signal perception mediated by nuclear receptors. These transcription factors are able to bypass the complex ‘second messenger’ signalling pathways
of surface receptors and directly link gene transcription to the availability of ligands coming from the surrounding environment.
Starting from 1985, when the first cDNA encoding the human glucocorticoid receptor was cloned, there has been an exponential growth in the knowledge covering the nuclear receptor field with more than a hundred thousand publications on this topic. As PhD students starting projects in the field we found that the available textbooks were not up to date and the task of mining the literature to compile a more contemporary picture proved to be very difficult. This new book offers a solid background in nuclear receptor biology, written by many of the leaders in the field, along with the most recent advances and will surely be an indispensable tool for researchers entering into the field.
As described in the ensuing pages nuclear receptors can sense steroid hormones, retinoids, dietary lipids, xenobiotics and many other ligands and quickly elicit a response. These actions are subject to an elegant regulation by a cohort of co-regulators, mainly co-repressor and co-activator complexes, that epigenetically modulate the chromatin environment through histone deacetylases and histone
acetyltransferases that, respectively, repress or promote transcription. Not surprisingly, nuclear receptors play a key role in normal physiology, adaptation to environmental conditions and in the development of diseases such as cancer where they are commonly exploited as therapeutical targets.  The widespread action of nuclear receptors easily explains why they are key hubs in cellular signaling within animals and why so many research projects focus on nuclear receptor biology, making it a very dynamic and constantly changing field of research. As PhD students, we have been motivated by curiosity and enthusiasm inthis kind of research. We hope that the readers of this book will be driven by the same passion.
Sebastiano Battaglia and Pedro Veliça Phd students with the editors, funded by the NucSys Marie Curie Research Training Network.