The Agamas are a collection of scriptures chiefly constituting the methods of temple construction and creation of idols, worship of deities, philosophical doctrines, meditative practices etc. Agamas deal with the philosophy and spiritual knowledge behind the worship of the deity, the yoga and mental discipline required for this worship, and the specifics of worship offered to the deity. The ritualistic pattern of worship in the Agamic religions differ from the Vedic form. While the Vedic form of yajna require no idols and shrines, the Agamic religions are based on idols with puja as means of worship. The Agamic religions are also called Tantrism, although the term ‘tantra’ is sometimes used specifically to refer to Shakta Agamas. The tantras are considered innumerable with various sects. Some popular agama-based religions are those of Shaiva, Vaishnava, Shakta, Ganapatya, Kaumara, Soura, Bhairava, and Yaksha-bhutadi-sadhana. The Shaiva Agamas revere the Ultimate Reality as Lord Shiva (Shaivism). The Vaishnava-Agamas adore the Ultimate Reality as Vishnu (Vaishnavism). The Shakta-Agamas (Tantras) venerate the Ultimate Reality as Shakti (Shaktism). Each set of texts expands on the central theological and philosophical teachings of that sect. There exist 28 Saiva Agamas, 77 Shakta Agamas and 215 Vaishnava Agamas, and their upa-agamas.
Each Agama consists of four parts
Kriya pada – consists of rules for construction of temples; for sculpting, carving, and consecration of idols of deities for worship in temples; for different forms of initiations or diksha.
Charya pada – lays down rules for daily worship (puja), observances of religious rites, rituals, festivals and prayaschittas.
Yoga pada – concentrates on yoga and the mental discipline.
Jnana pada – consists of philosophical and spiritual knowledge, knowledge of reality and liberation.
Elaborate rules are laid out in the Agamas for Silpa (the art of sculpture) describing the quality requirements of the places where temples are to be built, the kind of images to be installed, the materials from which they are to be made, their dimensions, proportions, air circulation, lighting in the temple complex etc. The Manasara and Silpasara are some of the works dealing with these rules. The ritual followed in worship services each day at the temple also follow rules laid out in the Agamas.