To which is added a discussion of problematic points and a complete set of tables necessary for the calculation of arcs of direction. This is essentially a book for the astrological student. The general scope of the work embraces all that is essential to the art of "directing" as practiced by Claudius Ptolemy and Titus de Placidus, and more recently by John Gladbury, Commander Morrison and A.J. Pearce, all of whom pursued the same general principles of astronomical directing and differed considerably in their application of the celestial arcs to the measure of time. These points are reviewed and critically examined within these pages.