Opening of the Way

https://www.hthakl-octagon.com/

This library is very well known.  Not sure if above is the same.
https://en.wikipedia.org/wiki/Bibliotheca_Philosophica_Hermetica

So Fraternitas Saturni was started in Berlin in 1928.

Right here:

Fire & Ice: Magical Teachings of Germany's Greatest Secret Occult Order (Llewellyn's Teutonic Magick Series)

The Brotherhood of Saturn is one of Germany's most secret occult lodges and unknown to magicians of the English-speaking world. This is the first study of its inner documents and workings. Discover the fascinating histories of its founders and leaders. Witness the development of its magical beliefs and practices and its banishment by the Nazi government. The Saturnian path of initiation is revealed in full detail.

by Stephen Edred Flowers, 1995 Llewellyn

and also

The Fraternitas Saturni: History, Doctrine, and Rituals of the Magical Order of the Brotherhood of Saturn (2018)
by Stephen E. Flowers Ph.D.

https://www.amazon.com/Fraternitas-Saturni-History-Doctrine-Brotherhood/dp/1620557215/ref=sxbs_sxwds-stvp?pd_rd_i=1620557215&pd_rd_r=e696a8b1-4085-44bd-b95f-fbe823551835&pd_rd_w=CJZZi&pd_rd_wg=JcJNJ&pf_rd_p=a6d018ad-f20b-46c9-8920-433972c7d9b7&pf_rd_r=WN7H2J2FMK3DSMBC4R5P&psc=1&qid=1581812061&refinements=p_27%3AS.+Edred+Flowers&s=books&sr=1-1-dd5817a1-1ba7-46c2-8996-f96e7b0f409c&text=S.+Edred+Flowers

look:
https://www.amazon.com/Fraternitas-Saturni-History-Doctrine-Brotherhood/dp/1620557215/ref=sxbs_sxwds-stvp?pd_rd_i=1620557215&pd_rd_r=e696a8b1-4085-44bd-b95f-fbe823551835&pd_rd_w=CJZZi&pd_rd_wg=JcJNJ&pf_rd_p=a6d018ad-f20b-46c9-8920-433972c7d9b7&pf_rd_r=WN7H2J2FMK3DSMBC4R5P&psc=1&qid=1581812061&refinements=p_27%3AS.+Edred+Flowers&s=books&sr=1-1-dd5817a1-1ba7-46c2-8996-f96e7b0f409c&text=S.+Edred+Flowers#reader_1620557215

The FS would be a huge influence on the London Crowley OTO successor Kenneth Grant!

Right here, available:

 Fire and ice 
  The Fraternitas Saturni : history, doctrine, and rituals of the magical order of the Brotherhood of Saturn / Stephen E. Flowers, Ph. D.  (2018, Inner Traditions, Rochester VT)

So Flowers has other books in libraries.  But they do not have:

Fire & Ice: Magical Teachings of Germany's Greatest Secret Occult Order (Llewellyn's Teutonic Magick Series)

Sex Magic thread
https://tuscl.net/discussion.php?id=70893

https://www.parareligion.ch/grosche1.html

So Grosche started his group, FS, in 1928.  The Nazi's prohibited it, but he got it going again after the war.  He continued till his passing in 1964.

https://www.parareligion.ch/fs1.htm

Any who have followed my posting might have noticed some years back that I found the absence of the Grotsch literary estate was a huge loss.  I feel that even more strongly now, but I would seem to be available!

I also like that this is being mediated by someone who is fascist politically conscious, as support for fascism is the Achilles heel for so much of this, people like Stephan Bannon.