The Mind's Eye is a series of articles from the later period of the third edition of Dungeons and Dragons when Wizards of the Coast was releasing expansions online relatively frequently. They were focused on psionics, psionic creatures and most importantly gem dragons and the deity Sardior. The Complete Psionic of the same era also heavily featured creatures formed from ectoplasm, and the entire concept was introduced (for the third edition) in the Psionics Handbook of 2001 (and its expanded version).
With the recent release of Fizban's Treasury of Dragons, it only made sense to revisit some of these articles and books to see what can be updated and brought into modern lore seamlessly. Though never explicitly stated, it appeared that there was a common theme throughout the Mind's Eye articles with the Demiplane of Ectoplasm found at the center. This book, along with the accompanying adventure MZA7 Dragonglass, is an attempt to explore that metaplot further.
In these pages, you will find information on the history, conditions, inhabitants and features of the Demiplane of Ectoplasm so that it can easily be used in a home campaign or be the actual center of a campaign in itself. You will also find magic that expands upon psionic abilities, particularly in the use of the substance of the plane's namesake.
- from the publisher's blurb