The Tirumantiram is the tenth of the twelve volumes of the Tirumurai, the key texts of Tamil Saivism. It is the first known Tamil work to use the term Shaiva Siddhanta and the earliest known exposition of the Saiva Agamas in Tamil.
The poems have a unique metrical structure, each line consisting of 11 or 12 syllables depending on the initial syllable. Tirumular discusses the four steps of spiritual progress; Charya, Kriya, Yoga and Gnana, the Shaiva Siddhanta concept of Pati, Pasu and Pasa, sadhana, Vedanta, the Upanishadic Tat tvam asi and other Vedantic concepts, the transcendental reality as emptiness (Sunya) devoid of any attribute and Tantrasastra (Shakti worship), chakras, magic spells and their accessories.
The section on Yoga, called "Shiva yoga", offers details not found in the Sanskrit text of Patanjali. The Tirumantiram describes means of attaining an immortal body (kaya siddhi), advocating a theory of preserving the body so that the soul would continue its existence (Udambai valarthen uyir valarthenae).
Tirumular as a moral philosopher teaches the ethics of non-violence (ahimsa), abstinence from slaughtering, meat and alcohol. He condemns coveting another man's wife but declares that "love is God", proclaims the unity of mankind and God and stresses the acquisition of knowledge.
The final section of the Tirumantiram, named Sunya Sambhashana ("Colloquy on the Void"), is full of metaphorical sayings communicating mystical and speculative thoughts, for example;