The second volume of Isis Unveiled, dealing with religion, although looser in structure, is nonetheless a sprawling, ambitious study in comparative religion. The first seven chapters mainly comprise a fairly detailed and original study of early Christianity through the first five centuries, relying on the studies of the time, mainly Supernatural Religion by Cassels, with the eighth chapter filling out the history of esoteric movements up to her time.
At the same time, the first eight chapters pursue other goals, mainly to critique perceived problems with the current Christian churches and pointing out the historical causes and to present a reform project by presenting an esoteric study of key Judeo-Christian theological concepts such as the Trinity and the Logos through perennialist comparative studies involving Hinduism, Buddhism, Greek Paganism, Zoroastrianism and Gnosticism, among others.
She has a notably pro-Gnostic stance, both Jewish and Christian, foreshadowing the remarkable resurgence of Gnosticism in the latter half of the twentieth spurred by the famous Qumran and Nag Hammadi discoveries. Indeed her writings are quite consonant with the contents of those texts, especially in her noting the importance of Jewish Gnosticism. She also presents groundbreaking research on Mandean Gnosticism with her use of the Ginza (Codex Nazareus). Morever, her portrayal of Jesus prefigures the alternative biographical studies of Jesus and the historical view of a simpler early Christianity that challenges the later assumptions of the Nicean council.
The final four chapters, are more focused and self-contained: chapter nine adds more study of theosophical concepts of spiritual evolution in ancient scriptures that prefigure the Secret Doctrine, chapter ten presents a specific critique of the dogma of the Devil, adopting a Miltonian/Masonic esoteric interpretation of the fall of Lucifer, chapter eleven gives a solid comparative overview of Hindusim, Christianity, and Buddhism while chapter twelve serves as a general conclusion for both volumes, emphasizing magical practices found in eastern religions.
With the remarkable subsequent rise of Hinduism and Buddhism, as well as Gnosticism, Sufism and the Kabbalah in the West and the continued decline and necessary reforms by the Christian churches, this work can be seen as remarkably prescient and influential (one is tempted to see this work as the founding charter for modern new age and alternative spirituality) and many of the ideas and contents are still relevant 140 years later.
The Basic ideas that govern both volumes can be summarized as follows:
1- Comparing, critiquing and contrasting ancient and modern science and religion (and rehabilitating the former);
2- Comparing ancient and modern western knowledge with eastern culture (and rehabilitating the latter);
3- Using the first two points (with wider comparative research) to posit the existence of a universal, perennial wisdom;
4- Using the first 3 points to introduce notions of esoteric philosophy;
5- Using these notions of esoteric philosophy to build a new synthesis of (a)ancient and modern science; (b) eastern and western knowledge; (c) science and religion.
6- Arguing for the idea of India as a pre-eminent cradle of civilization.
7- Critiquing and clarifying the problem of spiritual phenomena and magic using esoteric principles.
8- Positing the existence of adepts who through their acquired spiritual knowledge, have been the caretakers of a primordial divine wisdom since the earliest existence of humanity.