The are three regions referred to in the story, Region 1920, where the book is set, and Regions 1819 and 2021. People are resurrected in cohorts spanning approximately a century according to what society they are going to feel most at home in when they are resurrected, with those born at the each end of the centuries resurrected into one or other of the overlapping regions. So:
- Region 1819 is where people born from the late 18th to late 19th centuries arrive
- Region 1920 is where people born from the late 19th to late 20th centuries arrive
- Region 2021 is where people born from the late 20th to late 21st centuries arrive.
The overlap at the beginning and end of each range is a general guideline that the Zoës may choose to override. The general idea is simply to avoid future shock.