Shaar HaGilgulim, Hakdamah 11, Lesson 4
The fulfillment of the 613 commandments in greater detail. The 248 positive commandments and the 365 negative commandments correspond to the 613 aspects of the astral/spiritual body (and not literally to the physical body). The energies underlying the commandments are the forms and parameters of natural law. Proper observance of mitzvot then gives rise to Qi energy within the body.
Certain commandments are observed physically, others are not.
How one reincarnates to fulfill one's destiny. How the fulfillment of destiny is actually the full manifestation of one's personality, at all its levels.
Regular reincarnation and ibbur (piggy-back reincarnation). How a soul can come to Earth and incarnate inside someone already alive for a short time to accomplish or experience something unique.