These are my favourite theological books, they're mostly to do with Christianity, however I've included Occult books in this section as well:
The bible, the central text of Christianity, must obviously be mentioned on a list of Theological books. As a Christian I frequently read the bible, usually every night if I'm not tired enough. There are number of different translations available to read the bible in, my personal favourite being the New Revised Standard Version: Catholic Edition, which includes the 7 extra Deuterocanonical books, I also however am a big fan of the King James Version, which I find to be written quite beautifully.
The Confessions, is an auto-biography of the life of Saint Augustine, detailing the events that led to his conversion to Christianity. The book also contains answers by Saint Augustine to a number of philosophical and theological questions which he considered during his conversion.
This book by father F.J. Koch is a very helpful guide to understanding the basics of Catholic theology and apologetics. The book covers almost all the major aspects of Catholic/Christian faith, explaining what is believed and why so. Definitely recommended for new or lukewarm Catholics wanting to learn more about their faith.
The Sword of Christ, by Giles Corey, explores the evolution of Christianity from the strong, traditionalist and Eurocentric church that once dominated the West, into the weakened, liberalized institutions which comprise Christendom in the modern age. He examines this decline from both the left and the right, attacking Liberal Christians for their ethnomasochism and attempts to transform Christianity into a deracinated, egalitarian religion which denies the existence of race; he simultaneously attacks Conservative Christians for their fixation with Christian Zionism, which Corey points out is deeply heretical, and has led to Western Christians tolerating an ethnoreligious group that despises them and their faith. The book concludes with an investigation into Christian violence, concluding that Christianity is not pacifistic, and Christians should act violently in the face of evil.
The Book of Enoch is one of the many books that make up the biblical Apocrypha (Books which were not included in the bible due to being of dubious authorship), it was written around 300 BC and claims to be written from the perspective of the pre-flood patriarch Enoch, the great grandfather of Noah. It tells of the world prior to the flood, and focuses on the events which led up to it, namely the birth of a race of giant men called Nephilim, who tormented and destroyed mankind.
A very useful text which provides a basic introduction to all sects of Western Occult thought, good for beginners who have no prior knowledge of Western Esoteric tradition.
An important book for anyone studying Esotericism. Written by 33rd Degree Freemason, Manly P. Hall, the book provides a detailed exploration of Western Esotericism from an Occult perspective. Covers many topics ranging from Pythagoreanism, Hermeticism, Kabbalah, Freemasonry and Rosicrucianism. The book also provides a very detailed breakdown of Kabbalah, going so far as to include the full transcript of the Sefer Yetzirah (The foundational text of Kabbalah).
A Science-Fiction book released in 1871, which tells the story of a man who discovers a highly advanced civilization deep inside of the earth, home to a race known as the Vril-Ya, who survive through the harnessing of Vril energy. The book is believed by many famous Occultists to be truth concealed as fiction, and the ideas in the book gave birth to the mysterious "Vril Society" in Nazi Germany. The concept of Vril and Vril energy remains still popular amongst Right-Wing Occultists to this day.
Theozoology is the work of Austrian Occultist Jorg van Liebenfels, it is an important book in the formation of Ariosophical thinking. Liebenfels argues in the book that Aryan peoples, are descended from a now extinct higher race of superhuman beings, created directly by God himself. He argues that the "lower races" (Blacks, Browns, etc) are primates or as he refers to "Sodomite Apelings" that are nothing more than violent and lustful animals. Liebenfels argues for a number of extreme measures to counter the defiling of the higher Aryans at the hands of the "Apelings", and tries to support his theories by suggesting the bible contains secret codes which prove his ideas true. The book has a number of flaws in its thinking, but nonetheless I found it to be a rather enjoyable read.
A metaphysical analysis of sexual ritual and desire written by the renowned Italian occultist Julius Evola. Explores the mystical and metaphysical reasons for, and ramifications of sex, drawing on tradition to support his points. Regarding the question of sex, this is certainly the best book on the topic in my opinion, and is certainly the basis for many of my views concerning sexual relations.
A collection of the main works of Robert Fludd, a 17th century English physician and occultist. His works primarily concern the relationship between the Macrocosm (God) and the Microcosm (Man), as well as the tripartite division of matter between Man, Earth and God. Also includes an interesting defence of the Rosicrucians against charges of Heresy