- Mitlanyal, Vols. 1-2 - A series of essays describing Pavar's pantheon including the five Gods of Stability, the five Gods of Change, and their respective Cohorts and demons. Mitlanyal also includes information on the Planes, Tsolyani astrology and descriptions of specific spells used by the priests of the various gods.
- Swords & Glory, Vol. 2 - The ultimate simulationist spell-list for magic in Tekumel. This is the most comprehensive spell corpus for modern Tsolyanu.
- The Book of Ebon Bindings - Tekumel's notorious book of demonology; since demons come from elsewhere and must be summoned, this book also discusses magic and the Planes.
- The Tongue of Those Who Journey Beyond: Sunuz (also known as The Grammar of Sunuz) - This text describes what is perhaps the oldest language still spoken on Tekumel: Sunuz, the language of the worshipers of the Pariah Deities. The very script of this language (which includes letters and numbers) is magical, and an understanding of this language and its script still influences magical practice on Tekumel today.
I've read most of the Mitlanyal, and this weekend I read The Grammar of Sunuz. The Grammar sheds light on many aspects of magic on Tekumel. The text begins strangely enough with an essay on scrying. Its core argument bears a family resemblance to Mao's 1963 essay "Where Do Correct Ideas Come From?" in the sense that it attempts to outline different sources of knowledge. It's an odd introduction, but its placement is important since Sunuz is the language used by worshipers of the three Pariah Deities: She Who is Not To be Named (the Goddess of the Pale Bone), the One Who Is, and the One Other.
Whereas Tekumel's gods are manifest and imminent, the Pariah Deities dwell in the Planes Beyond. They seek to consume this and other Planes. In this sense their interests and orientations are quite alien to those of the deities of Tekumel, who for the most part are involved in the affairs of this Plane and arguably "care" to greater and lesser degrees about what happens to their worshipers. None of this is the case with the Pariah Deities, however much they reward their worshipers.
One has to look far (i.e., far into the Planes Beyond) in order to reach, see, and communicate with these inimical deities. The letters and numbers of the script of Sunuz give you the tools for doing that, as well as for protecting oneself from the Pariah Deities' deadly influence. Just ask the tattooed Livyani.