Its been around virtually as long as Astrology. In the form I use, it is derived from the work of William Lilly, the Seventeenth Century English Astrologer. However he used techniques which he derived from the Arab Astrologers of the eleventh and twelfth centuries. Doctor John Dee who functioned as an advsior to Elizabeth I also seems to have used similar techniques. Lilly also forecast the Great Fire of London so accurately that he was summoned to a Parliamentary Committee to explain how he knew so much about it.
Horary, along with other traditional branches of Astrology, such as Medical, and Electional flourished into the twentieth Century. However the developmen of psychological Astrology by Dane Rudhyar and followed up by Liz Greene led to something of a rejection of traditional methods. For Horary, Saturn is a malefic planet but in psychological natal astrology it receives a more constructive interpretation. Horary survived though and there are still many practicing Horary Astrologers. Recently there has been a revival of interest in traditional techniques - Rob Hand's Project Hindsight is a good example and has an excellent web site.
The work of Marc Edmund Jones, Sue Ward, Olivia Barclay, Carol Wiggers, John Frawley, Linda Reid, Lee Lehman and many more have turned Traditional Astrology into a thriving area. Tony Louis, who wrote Tarot Plain and Simple is a practicing Horary Astrologer (and psychiatrist), he also wrote Horary Astrology Plain and Simple - both books are published by Llewellyn.
I notice now that many of the earliest texts of Astrologers are being republished so you might find works by Dorotheus, Manilus, Fermicus, Al Biruni, and Avraham Ibn Ezza appearing on the bookshelves of specialist Astrology bookshops.
