Full-color illustrations to supplement the audiobooks and print books:

Illustrations - Rolo the Pet Earthling
Illustrations - Planet of the Cats
Illustrations - Jack Bones

Literary analysis of plot structure, themes, setting, tone, etc., plus details on each chapter:

Literary Analysis - Rolo the Pet Earthling
Literary Analysis - Planet of the Cats
Literary Analysis - Jack Bones

The science facts behind the science fiction:

Science of Rolo the Pet Earthling
Science of Planet of the Cats & Jack Bones