I would like to thank Chris Haviland and Carol Long from Wiley, to make this book happens, take the risk, turning and curating a vast amount of valuable but unstructured and scattered text published online, into a coherent, comprehensive and useful book. In many ways, this complex process is similar to turning unstructured into structured data, a challenge many data scientists face on a regular basis, with solutions provided in this book. Also, I would like to thank my business partner and co-founder Tim Matteson, who helped grow Data Science Central to not only the leading data science community, but also to a modern, lean start-up focused on delivering value. Finally, I want to help all the members of our community, for their numerous comments and support. Without them, this book would not exist