Ball lightning is discussed in the book and is considered a plasmoid, which is a form of plasma. The book suggests that ball lightning can be looked upon as a plasmoid, specifically a crystalline plasmoid or plasma crystal. It is also mentioned that ball lightning can interact with electricity and is considered an electric phenomenon. Additionally, the book connects ball lightning to the concept of plasma beings and reincarnation, suggesting that all living entities in the world of physical matter, including humans, are plasma beings temporarily incarnated in physical bodies. This relates to the content of the book as it delves into the nature of plasma and its connection to various phenomena.