Astronomers' Universe Series is a new series aimed at active amateur astronomers but is appropriate to a wider audience of astronomically-informed readers. The book provides an up-to-date account of active galaxies. Lists of such objects and their visual and imaged appearance in commercially available telescopes are an important component of this book. The book makes sense of the chaotic and apparently innumerable types of violently active galaxies. It provides the data and teaches the skills needed for users of small telescopes to observe and image some of these "galaxies in turmoil" for themselves.