ASTROLOGICAL SYSTEMS are based on the premise that there is a relationship between astronomical phenomena and the human world. Astrology, different from astronomy, is a natural science which is the study of celestial objects. The roots of western astrology can be found in Mesopotamia in the 2nd millennium BCE. Chinese astrology was commonly practised in the Zhou dynasty (1046–256 BCE). In India complicated astrological systems based on celestial observations emerged as early as the 1st century BCE. Many ancient civilisations searched for meaning in the sky. Referencing astronomical rhythms helped to predict seasonal changes. Lunar cycles were recorded as early as 25,000 years ago. Constellations were observed and recorded. Their appearances were referenced to the seasons and helped to predict annual floods and initiate seasonal activities such as planting and harvesting. The procession of cosmic bodies was related to philosophical elements, body organs, personality types and states of mind. It was believed that astrology explained everything about a person’s fate and destiny. In modern times astrology is considered a non-science. Scientific testing of astrology has found little evidence to support the effects claimed in astrological traditions. However, astrology has never lost its fascination, and for many people it is a reliable alternative guide to looking at the world and understanding its subtleties. This Guide provides a practical and useful overview of the four most prominent astrological systems.