Primary sources for the 19th century roots of the Church of Light:
The Hermetic Brotherhood of Luxor: Initiatic and Historical Documents of an Order of Practical Occultism (1995), edited by Joscelyn Godwin, Christian Chanel, John Patrick Deveney, is the starting point for exploring the roots of the Church of Light. This collection includes the documents and private lessons of this initiatory order, as well as correspondence among members in Europe and America.
Ghost Land (1876) by Emma Hardinge Britten is the alleged memoir of Britten’s European occultist colleague the Chevalier Louis, and combines fiction and fact in ways that baffle modern researchers. It describes the Orphic Circle as a group of experimenters into clairvoyance, mesmerism, spiritualism, etc. In addition to the free online edition available through the SSOC (Standard Spiritualist and Occult Corpus) there is a forthcoming definitive edition from Typhon Press featuring introductory essays from four scholars, and multiple reprints available. The most recent reprint is from the Cambridge University Press, 2014.
Art Magic (1876) by Emma Hardinge Britten is a companion doctrinal work attributed to the same narrator, and with Ghost Land was studied by the HBofL and its successors into the 20th century. In 2011 a scholarly edition with introduction and annotations by Marc Demarest was published by The Typhon Press.
The Light of Egypt (1889) by T.H. Burgoyne is the major doctrinal book by a founder of the Hermetic Brotherhood of Luxor. An astrological emphasis that began with the Chevalier Louis increases with Burgoyne.
Esoteric Lessons (1900) by Sarah Stanley Grimke is a posthumously published collection of three shorter works: Personified Unthinkables (1884), First Lessons in Reality (1886), and A Tour Through the Zodiac. Grimke collaborated with Burgoyne on the astrological portions of The Light of Egypt.
The Quest of the Spirit (1913) by Genevieve Stebbins is the accumulated life wisdom of a man known as “A Pilgrim of the Way,” almost certainly her husband Norman Astley. It represents a radical shift of emphasis from Hermetic Brotherhood of Luxor teachings, and reveals Stebbins and Astley to be devotees of Henri Bergson and William James rather than occult tradition.
Zanoni (1842) is a novel by Edward Bulwer-Lytton that portrays its adept heroes as Rosicrucians. Burgoyne took Zanoni as his pen name, and his colleague Peter Davidson took that of Mejnour, the master of Zanoni. Britten named Bulwer-Lytton first among her Orphic Brotherhood mentors, and Blavatsky named him as an adept in a letter to a friend. (link to second volume here.)
The Quest for Hermes Trismegistus (2011) by Gary Lachman is an indispensable guide through the Hermetic tradition for the contemporary reader.
Occult America (2009) by Mitch Horowitz provides an entertaining tour through American religious history, with coverage of the Church of Light and the Theosophical Society among more than a dozen groups discussed.
A Republic of Mind and Spirit (2007) by Catherine L. Albanese is a sweeping survey of metaphysical religion in America, emphasizing the Hermetic roots of many 19th century movements like Theosophy and New Thought
Hidden Wisdom (2006) by Richard Smoley and Jay Kinney, provides a knowledgable guide to Western Inner Traditions by two authors who were co-editors of Gnosis Magazine.
The Theosophical Enlightenment (1994) by Joscelyn Godwin places the occult revival in context of British literary history of the 18th and 19th centuries, with Britten and Blavatsky both treated as pivotal figures.
The Masters Revealed (1994) by K. Paul Johnson consists of brief biographies of Blavatsky’s mentors and teachers in chronological order. Part 1 describes 14 adepts from Europe, America, and the Middle East. Part 2 focuses on 18 Asian Mahatma figures who shaped Theosophy after its headquarters were transferred to India.
Paschal Beverly Randolph (1997) by John Patrick Deveney is a masterly biography of the enigmatic African American Rosicrucian author whose global wanderings produced a body of teachings that embraced drugs, sex, and magic mirrors. His teachings were known and cited by the founders of the HBL.
The Masonic Myth (2009) by Jay Kinney explores International Freemasonry as the primary network for transmission of occult ideas in the 18th century which continued as a powerful factor in the 19thcentury occult revival. Kinney’s new book explains the roots of Masonry and its later incorporation of Hermetic, Kabbalistic, Islamic and theosophical themes.
Primary sources for pre-19th century background:
The Magus by Francis Barrett (1801) is a compilation of magical literature from the Kabbalah through the Rosicrucians.
Thrice Greatest Hermes is the Corpus Hermeticum, the central scripture of Hermetic religion.
Tetrabiblos by Claudius Ptolemy is the classic textbook of astrology.