The Third Reich is another World War II series, but this one is specifically focused on Germany and the Nazis. For whatever reason, the Nazis seem to be one of the more interesting groups to arise in the past 100 years and despite their politics people keep reading about them. About the only reason I can think of to study the Nazis is to make sure no one else that radical manages to gain that much power.
I haven't read any of these yet, so I can't vouch for their value, but just from flipping through it seems likely that they're very well done.
I have gotten some feedback from people looking for Empires in the East and Homeland Beseiged that say they were cancelled before they were published. Does anyone know definatively that these books were (or were not) published? As of right now, judging by the Library of Congress record and the volume list published in the series itself, I'm assuming that these two books were never published in the US, so if you know otherwise please let me know!