Chapter 1 – Lesson 1   The Buddha, just prior to the 7th annual rains retreat (vas), i.e. 7 years after Enlightenment, ascended to the Tavatimsa heaven, to deliver the sermon on Abhidhamma to thousands of Devas and Brahmas who assembled there, from ten thousand world systems, including His mother, who was then born as a Deva in Thusita Heaven. There, seated on the ‘Pandukambala’ stone seat of God Sakka, He preached the Abhidhamma, in detail, for a continuous period of 3 months. It was expounded to the heavenly beings, as it had to be explained to the same...