The book is available in several formats from major retailers:
Fate of Worlds is unique because it serves as the fifth book for two separate series that finally merge into a single conclusion. Fate of Worlds: Return From the Ringworld
Narrated by Tom Weiner, found on Audible and Google Play. Fate of Worlds: Return From the Ringworld | Skiffy.ca The book is available in several formats from
Ringworld (1970), The Ringworld Engineers (1979), The Ringworld Throne (1996), and Ringworld’s Children (2004). The Ringworld Engineers (1979)