[1] Frykenberg is known for his seminal book, Guntur District, 1788-1848: A History of Local Influences on Central Authority in South India,[2][3] This book informed all his subsequent works: e.g. traditional processes of power, land control and social structures, educational institutions, language issues, conversion movements, urban formations, and religions such as Christianity and "syndicated" modern Hinduism.

[6] An Indo-centric perspective underlies all Frykenberg's works from his Guntur District, 1788-1848: Local Influences on Central Authority in South India (1965) onwards.

[7] In her review, Kristin Bloomer declared, "Until now, no single book in English had attempted to cover the vast topic of Christianity in India.

[18] One of Frykenberg's articles in 1986 showed how, during the emergence of modern education, command of English was driven by local communities working with the Raj.

He highlighted how missions influenced religious renewal, social reform, and nationalism, noting that their success was often greatest when they operated far from the centers of imperial authority.

[23] In The Sacred in Twentieth-Century Politics, he examined Hindutva fundamentalism as a militant nationalist movement that aims to establish a hegemonic Hindu nation through religious symbolism, caste hierarchy, and cultural homogenization.

The work highlighted conflicts between Tamil Pietist leaders and the ecclesiastical authority of colonial Anglicans.