Why Shiv-Tattva-Ratnakar?
Why I always prefer Shiv-Tattva-Ratnakar?
The reason is simple , it was composed by none other than Basavaraja Bhupala , the son of Keladi Chennamma Chetti . This Granth is not only an important text for Vīraśaivism but its also an encyclopedia.

From basic "types of head nods" to svadharma and from history of keladi Nayakas to philosophy of vīraśaivism it covers everything! Literally everything from how to swing a sword to how to make it !

It's the most authentic and trustworthy text for the history of vīraśaivism and keladi Nayakas as
1. It's samkalin(of same type)
2. It's written by one of the keladi Nayaka himself .