Some consider him the father of modern astrology: in the early 20th century, prominent British astrology Alan Leo opened up the secrets of divination by the stars to the general public with his line of "Modern Astrology" manuals, a popular series of books that set off a craze for horoscopes that continues to this day. Here, in this 1915 guide to the red planet, Leo explains the power of Mars over the zodiac-and over the human spirit-from its sway over the conscience to its command of the passions. How does Mars stimulate greed, stir the martial senses, and inspire rage? Leo explains the strange rule of the planet of war over us all.