Book excerpt: Dasa gives a system whereby we see the results which impact the native in a time period. Each Dasha is controlled by one planet. It is the disposition and relationship of this planet, that the promised events are reflected. The results which a planet promises in its Dasa has to be studied by a careful analysis of the planet. The Vimshottari Dasha is a 120 year cycle of planetary position based on the position of Moon in one of the lunar mansions called Nakshatras. We have started the book explaining various Dasas. The first basic principles have been explained at length. In the next part we go in details, discussing the strength of the planet depending upon position of planets, lordship and various rules that modify the strength. Each Dasa and its predictive aspect are explained in details. It takes into consideration the sign in which the planet is posited. It also explains the effect of directional strength, state of the planet and the divisional strength. This will enable the reader to make an overall assessment of the planet whose Dasa is being analyzed for a native. The next part dwells with the rules that have to be followed while taking the impact of Sub Period in the major period (Dasa) of the planet. We have in details discussed factors that strengthen or weaken the result which is promised. Further the impact of other vectors, like the transit and strength have been explained.