B.V. Raman’s literary estate is currently managed by his descendants and the Raman & Rajeswari Research Foundation. The unauthorized distribution of his books as "exclusive PDFs" poses a significant challenge to the preservation of his work.
If you read only one book, read this. First published in 1938, this is the Kama Sutra of planetary periods (Dasha systems). It explains how to use the Vimshottari Dasha in a practical, step-by-step manner. Exclusive versions of this PDF often come with a bonus section on Ashtakavarga that is missing in cheap reprints.
The legal sources are:
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