The Great School of Magic
Something bugged me a long time ago. It was the Gazetteer 3 Principalities of Glantri; a really outstanding work by our beloved Bruce Heard, our Mystara Spirit. The book gave us stacks of intense, and usable information. Yet it also gave some incomplete material. The AD&D2 adaptation of Mystara and the Glantri Kingdom of Magic, Wrath of the Immortals, Poor Wizard Almanacs, Castle Amber, DM Survival Guide and Players Survival Guide, added some more information, but holes stayed, or more were created due the awful AD&D2 conversion of GKoM. Many flaws have crept in, and areas left open. Areas you actually need in playing the Great School of Magic in Glantri on Mystara, BECMI style (or actually any D&D style)!!

I searched and searched, found and compiled, not only from the canon sources, but also with the help of some fan work. I earlier had created some Isometric maps of the Great School of Magic In Glantri City based on the initial interior cover map of the GSM. in 2016 I rediscovered these maps, and decided to make two more Isometric maps from other directions, enabling the Great School of Magic to be viewed from all directions. With this, more detail came on about the inside, and following the canon sources together with architectural laws for stability, strength, and consistency I now even created the inside floor plans, first in pencil, later clarifying with Windows Paint. Rereading all the canon and fanon sources, more information was added, a timeline came forth, and the various uses canonically of the rooms made even more clarity. 
Using the interior maps that came forth after the creation of the Isometric maps and using architectural sanity, I thus created the Great School of Magic of Glantri as presented canonically in the Mystara various compiled sources(including many more small bits & pieces from fans). I continued to stray further…and deeper, higher…a strange habit I know, but it brings even more clarity and depth, but specifically multidimensional reality. I expanded the Magical Circles, to bring more magic in the world. I also took many items and spells from other D&D sources, and some self-created to bring more magic use and feel.
without further ado; I am now ready to present you Glantri Great School of Magic In detail …and scent, and touch, and sight, and magic, and material, and use ….etc, as best I could compile and create together in 17.5 months of continuous work. 

One interactive PDF book; where each link clicked (with CTRL at the same time) directs you to sources of information. 
Each door is thus attached to a link within the document leading towards the room which door you have chosen, making it almost as if you really wandering through the whole structure.

55 maps and cutthroughs; including 3 Isometric maps of GSM, 1 Sideview Of GSM, 1 readjusted map of GSM Gaz3, 
several section maps of GSM, 6 Historic Maps of Redfen and Braejr, 2 future maps of Principalities of Glantri, 
1 cutthrough of the GSM with Shell of Darkness growth explained, 
408 new or adjusted spells (adjusted from AD&D2 to BECMI, or really new self-created), 
Expansion on the various secret craft mages of Glantri, 
Detailed information on elementals & invisible Stalkers & Faenare & Griffons, 
several New creatures,
100 new Magical items(adjusted from AD&D2 to BECMI, or really new self-created), 
1 Major Artifact with full campaign, 1 major dimensional room, 
common use of Dimension Doors (various types), 
34 stone colors/types, 23 Skills (new and older) updated and expanded, 
8 Diseases & afflictions, 
Information on mage Courtyard Arena battles, 
Several useful tables, 
The future of Glantri and the Radiance, 
74 adventure suggestions attached to the locations, 
and a lot more interesting stuff, secret stuff, wondrous stuff and obscure stuff...spread over 19 levels, 2 major locations, and hundreds of rooms and other areas.

in total 555 pages, 41.6 MB. 


All this you will find in "Glantri Great School of Magic in Detail".
see here too; http://pandius.com/gsomdtl.html for all combined maps

So have fun and enjoy this Compilation book.