Dear Martin,

Besides the excellent resources already pointed out (Nijenhuis, T.M.Krishna), here are some more:

Sakuntala Narasimhan (1999) is a good place to begin. R.Sathyanarayana (2004) is a general history of genre, raga and other elements of Carnatic music over the last 5 centuries. The introductions of Sathyanarayana (2002), (2006), and Hema Ramanathan (2004) are very helpful to get a synoptic account of the raga system for South Indian classical music, and cover the period 16-19 centuries. The articles by N.Ramanathan  give diachronic accounts of the changing notions of raga and mela. 

For North Indian classical music, Deepak Raja (2015) may be helpful (albeit whimsical) as he will often refer to published recordings as illustrations.

Best regards,
Naresh Keerthi

Naresh Keerthi
Head and Assistant Professor
Department of Sanskrit Studies
Ashoka University

recent articles :
Thinking on Six Feet: The Joy of the Kannadakuvalayānanda
Kawisamaya: Towards an Ecocritical Account of Kakawin Literature

Narasimhan, Sakuntala. 1999. All You Wanted to Know About Indian Music but Didn't Know Whom to Ask. Bangalore: Veenapani Centre.

Raja, Deepak.S., 2015. Raga-ness of Ragas-Ragas Beyond the Grammar. Delhi: D.K. Print World Limited.

Ramanathan, N. “The Concept of Mela, by N Ramanathan,” MusicResearchLibrary, accessed June 24, 2024, http://musicresearchlibrary.net/omeka/items/show/2318.

Ramanathan, N. “The Concept of Raga, by N Ramanathan,” MusicResearchLibrary, accessed June 24, 2024, http://musicresearchlibrary.net/omeka/items/show/3024.

Ramanathan, Hema. 2004. Rāga Lakṣaṇa Saṅgraha. N. Ramanathan.

Sathyanarayana, R. 2004. Karnataka music as aesthetic form (Vol. 14). New Delhi: Project of History of Indian Science, Philosophy, and Culture, Centre for Studies in Civilizations.

Sathyanarayana, R. 2002. Caturdaṇḍī Prakāśikā of Veṅkaṭamakhin. Vol. 1. 2 vols. New Delhi: IGNCA and Motilal Banarsidass Publishers Pvt. Ltd.

Sathyanarayana, R. 2006. Caturdaṇḍī Prakāśikā of Veṅkaṭamakhin, Volume II, Makhihṛdaya, A critical study. New Delhi: IGNCA and Motilal Banarsidass Publishers Pvt. Ltd.

Sathyanarayana, R. 2010. Rāgalaḳsaṇam. New Delhi: IGNCA and Motilal Banarsidass Publishers Pvt. Ltd.