In connection with this, let me tell you before, that since you seem so interested with the subject, you can do nothing better than to study the two doctrines — of Karma and Nirvana — as profoundly as you can. Unless you are thoroughly well acquainted with the two tenets — the double key to the metaphysics of Abidharma — you will always find yourself at sea in trying to comprehend the rest. We have several sorts of Karma and Nirvana in their various applications — to the Universe, the world, Devas, Buddhas, Bodhisatwas, men and animals — the second including its seven kingdoms. Karma and Nirvana are but two of the seven great MYSTERIES of Buddhist metaphysics; and but four of the seven are known to the best orientalists, and that very imperfectly.
If you ask a learned Buddhist priest what is Karma? — he will tell you that Karma is what a Christian might call Providence (in a certain sense only) and a Mahomedan — Kismet, fate or destiny (again in one sense). That it is that cardinal tenet which teaches that, as soon as any conscious or sentient being, whether man, deva, or animal dies, a new being is produced and he or it reappears in another birth, on the same or another planet, under conditions of his or its own antecedent making. Or, in other words
Abhidharma (Sanskrit) or Abhidhamma (Pāli) are ancient Buddhist texts which contain doctrinal material appearing in the Buddhist Sutras.