Iraiyaṉār Akapporuḷ, or Kaḷaviyal eṉṟa Iraiyaṉār Akapporuḷ, literally "Iraiyanar's treatise on the love-theme, called 'The study of stolen love'" (Tamil: களவியல் என்ற இறையனார் அகப்பொருள்) is an early mediaeval work on Tamil poetics, specifically, on the literary conventions associated with the akam tradition of Tamil love poetry. The date of the work is uncertain, but it is generally taken to have been composed between the fifth and eighth centuries.
The Akapporul consists of a set of sixty nūṟpās - terse epigrams written in verse which codify rules - attributed to Iraiyanar. The received text of the accompanied by a long prose treatise on akam poetics attributed to Nakkiraṉār, which is structured as a commentary on the nūṟpās, but significantly expands on them and introduces several new ideas. The work as a whole occupies an important place in the history of Tamil literature for several reasons. The poetical argument of the work, and in particular Nakkiranar's treatment of traditional love episodes as successives scenes in an unfolding drama, was extremely influential in the development of Tamil love poetry and poetics in the mediaeval and pre-colonial periods. Secondly. Nakkiranar's treatise is both the first major Tamil work to be written entirely in prose, and the first erudite textual commentary in Tamil, and as such stylistically shaped the development of the Tamil prose and commentarial traditions. Finally, the work also contains the oldest account of the Sangam legend, which has played a significant role in modern Tamil consciousness.
The Iraiyanar Akapporul in its present form is a composite work, containing three distinct texts with different authors. These are sixty nūṟpās which constitute the core of the original Iraiyanar Akapporul, a long prose commentary on the nūṟpās, and a set of poems called the Pāṇṭikkōvai which are embedded within the commentary.
The original Iraiyanar Akapporul consisted of sixty brief verses - called nūṟpās - that, in total, contain 149 lines. The verses show a number of similarities with the poruḷatikāram section of the Tolkappiyam - an old manual on Tamil grammar, poetics and prosody - both in its vocabulary and the core concepts it discusses. Takahashi suggests that this work was originally composed as a practical handbook for writing love poetry in accordance with the conventions of the akam tradition. The intent behind its composition, according to him, was to produce something that was more accessible and useful to poets than existing theoretical works on poetics, such as the poruḷatikāram.