Kalyana Varma, the famous author Saravali belonged to the 10th century AD. He was the king of a place called Vyaghrapada, believed to be somewhere in Madhya Pradesh. From the verses in this work it is obvious that he has studied the works of Parashara, Varahamihira and Yavana etc before him, and as he felt that they were too brief, he decided to elaborate the principles. Saravali indeed is a monumental work and the study of it is a must for the serious students of astrology.
The original book BHRIGU SUTRAS, which I am translating has no introduction whatsoever and hence, I am unable to say anything about the author thereof. It gives valuable hints and aids, in delineating the character & fortunes of a native , in various walks of life. What is popularly known as Bhava Phala (effects of the 12 houses) in standard texts, is dealt with a direct touch, and with particular reference, to the planets stationed in various houses, the aspects they receive and the fact, that a planet is in exaltation, own or enemy house. Even a cursory perusal of the book, would convince even a professional astrologer, that this book can enable astrologers, to predict the future of a native, and form an opinion about planetary dispositions in a horoscope, with a fair amount of ease.