"Active Galactic Nuclei" by itself is a boring title that is not even unique to this book;  "Active Galactic
Nuclei: From the Central Black Hole to the Galactic Environment", although unique and descriptive , is more than a mouthful.    Many friends, readers, and especially members of my family have suggested titles they thought would be improvements (my wife has been the most prolific source).   The alternate titles I've collected so far are listed below; I invite others to make suggestions.  With any luck, maybe we'll be able to persuade Princeton University Press to adopt a title for the second edition that's more fun.
 
 

"Radio Galaxies are from Venus, Quasars are from Mars"

"Rid Yourself of Codependency on Active Galactic Nuclei: A Twelve-Step Approach"

"You'll Never Eat Lunch in this Cosmos Again: Accreting Black Holes in Active Galactic Nuclei"

"Every Galaxy Can: Building Self-Esteem in Your Galaxy by Growing Supermassive Black Holes"

"The Angel in the Black Hole: Otherworldly Spiritual Adventures with Relativistic Jets and Advection-Dominated Accretion in Active Galactic Nuclei"

"Paws in the Black Hole: Your Pet and Active Galactic Nuclei"

"The Monster (or the Monkey) in the Middle: Black Holes in Galactic Nuclei"

"Sexually Active Galactic Nuclei"