THIRUVARUTPAYAN OF UMAPATHI SIVACHARYA
Translated with Notes and Introduction by J. M. Nallaswami Pillai first published in 1896.

The Vedas and the Sivagamas in Sanskrit and the Tirumurais and the Siddhanta Sastras in Tamil are the principal scriptures of Saiva Siddhanta. The four authors of the first eight of the Twelve Tirumurais are called the Samaya Acharyas. They are St. Tirugnana Sambandar, St. Tirunavkkarasar, St. Sundaramurthi, and St. Manikkavachakar. The hymns of the first three are generally known as Thevaram, and those of the last as Tiruvachakam. These living hymns of the Samaya Acharyas which are well-known for their intensity of devotion and spiritual uplift, and for their matchless beauty of expression contain also all the fundamental ideas of Saiva Siddhanta. The tenth Tirumurai viz., Tirumantiram by St. Tirumular, which was composed some time before the 6th century A. D. , gives the essence of the Sivagamas, and a more or less systematic account of the Saiva Siddhanta Philosophy.