The entire cosmos, from top to bottom, encompassing all its fascinating and terrifying variety, is saṃsāra. It is the arena of all manifestation, action (kamma) and result of action (vipāka). It is dependently arisen, contingent, imperfect, and all forms within it are impermanent and subject to change and dissolution.
This book details the early Buddhist view of the cosmos. Using mostly Pali sources, Punnadhammo Mahathero covers topics such as time, space, the various realms, and the qualities of the beings that inhabit them.