As everything in this universe happens for a reason, there must be some reason why Sun and Moon move in forward direction only, Rahu and Ketu move in backward direction only, whereas Jupiter, Venus, Mars, Mercury and Saturn move in forward as well as in backward direction. Therefore we will deal with these five planets through this series of books and we will see what positive or negative effects they can cause; placed in different houses of a horoscope, when they go retrograde.