Spiritualism was a big part of the late Victorian age. Not simply Occult, Spiritualism dealt specifically with the communication with those beyond death.
The first part of this book details this well. The second part discusses how all of this plays out in the Imperial Age game, including the different sorts of campaign modes one might choose.
We are also given a new Advanced Class, the Medium and plenty of new feats, magic.
Again, most of this book is "system free" so it can be used in any game. The d20 specific stuff is still quite useful.
All the Imperial Age books are all well written and features art from the age, either public domain art and paintings as well as some original art. In all cases the art is very evocative of the time and very well done.
The books are all easy to read, with clean layout and font sizes. They can be printed with ease without killing your printer cartridge.