Order of Cluster Books

Piers Anthony's Cluster series presents a vast science fiction universe where humanity has established Sphere Sol, a 100-light-year-diameter region of galactic territory centered on our sun. This sphere represents humanity's zone of influence, while other alien races maintain their own spheres around different star systems. Throughout this galactic civilization, species expand their reach across planets using three distinct methods: mattermission (a form of teleportation), traditional freezer ships, and lifeships.

Anthony launched this ambitious series in 1977 with the inaugural novel *Cluster*, continuing the saga through four additional books until its conclusion with *Viscous Circle* in 1982. The five-book series unfolds in both publication and chronological order, creating a cohesive narrative arc across the sprawling interstellar setting.