Tirumandiram

The Thirumantiram is a Tamil poetic work written in the fifth century by Thirumular and is the tenth of the twelve volumes of the Tirumurai, the key texts of Shaiva Siddhanta and the first known Tamil work to use the term. The Tirumantiram is the earliest known exposition of the Shaiva Agamas in Tamil. It consists of over three thousand verses dealing with various aspects of spirituality, ethics and praise of Shiva. But it is more spiritual than religious and one can see the difference between Vedanta and Siddhanta from Tirumular's interpretation of the Mahakavyas. According to historian Venkatraman, the work covers almost every feature of the siddhar cult of the Tamils. According to another historian, Madhavan, the work stresses on the fundamentals of Siddha medicine and its healing powers. It deals with a wide array of subjects including astronomy and physical culture.

In short, the Tirumandiram, strongly emphasizes on Love is God, (Anbey Sivam).

The Tirumantiram is divided into nine chapters, 9 tantras (tantirams);

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 where Pati stands for Lord shiva, Pasu stands for the human kind and Pasa stands for Maya (the desire), 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.

...
Wikipedia