The Math of Astrology is a simple, methodical, step-by-step guide for manual chart calculation with pencil and paper. Often perceived as difficult, chart calculation is in fact a skill easily mastered with practice. Basic arithmetic is used with each formula to determine sidereal time, planetary positions, and house cusps. Manual chart calculation offers an extra benefit: the process leads to a deeper understanding and interpretation of the chart, which "comes alive" as each step in erecting the chart is completed. In addition to learning how to manually calculate a natal chart, the authors also present step-by-step instructions for calculating the secondary progressed chart, secondary progressed angles, and the Part of Fortune and Part of Spirit. You will also learn how to calculate secondary progressions for a specific date and time, as well as return charts (solar, lunar, and planetary), relocated charts, declinations, aspects, and midpoints. There is also a helpful chapter devoted to detecting and correcting errors in chart calculation, and worksheets that can be photocopied and used during each step, from natal to progressed to return chart. Also included is a chapter on the basics of natal chart interpretation, and another that offers interpretation guidelines for the progressed chart. The latter introduces the concept of cycles, the value of progressions in forecasting, delineation of the progressed Moon through the houses, and delineation of aspects made by the progressed Sun.