A Rectification Manual presents the first synthesis of medieval astrology's predictive techniques applied to natal chart rectification. For too many years, an incomplete predictive model has hampered efforts by astrologers to compute an accurate birth time. With no consensus on rectification methods, rectified birth times are commonly held in such disrepute they rank on par with dirty data, as defined by Astrodatabank, a leading astrology database vendor. With the recovery of medieval predictive techniques, the era of disenchantment over rectification is now over. Not just Transits, Progressions, and Solar Arcs; but techniques ranging from Firdaria to Primary Directions to Zodiacal Releasing fill out a complete predictive toolbox. For the first time, proper attribution between life events and corresponding predictive methods is now possible; making accurate rectification an achievable feat. Rectified to-the-second birth times for each American President are included. A Rectification Manual is the largest collection of natal charts subjected to medieval predictive techniques available in today's marketplace.