There are many wonderful resources for the study of Divya Desams, temple architecture, and Vaishnava philosophy in English and Tamil. Some of them were used in creating the content for this website.
“108 Divya Desam – Vaishnava Yatra” (Saila Sudha Trust, Chennai, 2014), a coffee table book with photographs by Avey Varghese, is a veritable visual treat and a good starting point to appreciate the sheer architectural variety and marvel of each of the temples.
“Philosophy and Theistic Mysticism of the Alvars” by S.M.S. Chari (Motilal Banarssidas, Delhi, 1997) is a well-researched book on the philosophical and theological underpinnings of the hymns of the Alwars and their influence on subsequent Vaishnava thought.
“The Book of Vishnu” by Nanditha Krishna (Viking, New Delhi, 2001) is an elegant book on the origins of Vishnu and his ten avatars, particularly suitable for beginners.
Besides these, there are thousands of books on these subjects, too numerous to suggest any meaningful list here.
There are many beautiful versions of the Ramayana, whose characters are closely interlinked to Thiruvanparisaaram. Originally written by the poet-sage Valmiki in Sanskrit, different versions of the epic exist, most notably in Tamil by Kambar and in Hindi by Tulsidas. The Ramayana itself is the subject of drama, poetry, song, dance, and popular culture, that has been revered, worshipped, and performed continuously in India and many south and southeast Asian nations for several centuries. For an outstanding English language translation of the original Sanskrit epic, refer to the Goldman series, a six-part series published by UC Berkeley, that has contributed substantially to scholarship on the Ramayana.
The web, of course, is a delightful resource, mostly unattributed but always entertaining. Youtube videos on the temple are a good starting point for those who are unable to visit the temple or are planning to do so. For those who are interested in listening to the Naalayira Divya Prabhandam or the 4000 Tamil hymns on the Lord, many versions exist on Youtube. The link below takes you to the sole reference in this work on Thiruvanparisaaram, composed by Nammalwar, considered to be the foremost among the 12 Alwars, and recited by Sri Velukkudi Krishnan: https://www.youtube.com/watch?v=fxtlLpNLpWY
Finally, a visit to the temple and its surroundings are the best way to understand the splendor, beauty, and sanctity of this Divya Desam, and how temples both intersect as well as form part of daily life in this and many parts of India.