This volume contains an English translation of Books 13, 14, 15 and 19 of the Astrologia Gallica, in which Morin explains the strengths of the planets, the division of the sky into celestial houses, the essential dignities of the planets, and the principles of judgment. These are fundamentals of horoscopic astrology. Morin was a physician who became the most renowned of all French astrologers. He was appointed Royal Mathematician to King Louis XIII and was present at the birth of the future King Louis XIV "The Sun King." His massive Latin work, Astrologia Gallica, was published in folio at the Hague in 1661. The present volume continues the series of English translations of those books of the Astrologia Gallica that are primarily devoted to astrological techniques. With its publication, Books 13, 14, 15, 18, 19, 21, 22, 23, and 24 are now available in English.