He is considered the father of modern astrology: Alan Leo opened up the secrets of divination aby the stars to the general public in the early 20th century with a popular line of astrology manuals that set off a craze for horoscopes that continues to this day. Here, in this replica of the 1910 fourth edition of his essential primer, Leo teaches us.. The basics of astronomy required for an understanding of astrology. The nature and character of the twelve signs of the Zodiac. Complete breakdowns of the affect of the Sun and the Moon on each house. What a horoscope is and how to cast one. And more.ALSO FROM COSIMO: Leo's The Key to Your Own Nativity, Symbolism and Astrology: An Introduction to Esoteric Astrology, Horary Astrology, and Mars: The War LordBritish astrologer WILLIAM FREDERICK ALLAN (1860-1917), aka Alan Leo, published Astrologer's Magazine as well as a line of astrological materials; he founded the Astrological Lodge of the Theosophical Society in 1915.