Reading order
| # | Title | Published | Author | Buy on Amazon |
|---|---|---|---|---|
| 1 | He Walked Around the Horses | 1948 | Henry H. Beam Piper | Buy |
| 2 | Police Operation | 1948 | Henry H. Beam Piper | Buy |
| 3 | Last Enemy | 1950 | Henry H. Beam Piper | Buy |
| 4 | Temple Trouble | 1951 | Henry H. Beam Piper | Buy |
| 5 | Time Crime | 1955 | Henry H. Beam Piper | Buy |
| 6 | Lord Kalvan of Otherwhen | 1965 | Henry H. Beam Piper | Buy |
| 7 | Paratime! Collected Paratime Stories | 2009 | Henry H. Beam Piper | Buy |
| 8 | Tales of Paratime | 2016 | Henry H. Beam Piper | Buy |
| 9 | Paratime Parasites | 2019 | Henry H. Beam Piper | Buy |
| 10 | Paratime Wars | 2020 | Henry H. Beam Piper | Buy |
The Paratime Police stories are built on a simple, appealing premise. One version of Earth discovered how to move between parallel timelines. They use this technology to trade with and exploit other Earths, none of which know about the secret. The Paratime Police are the agents responsible for keeping it that way. Verkan Vall, a senior Paratime cop, is the recurring main character.
Piper introduced the concept in “Police Operation” (1948) and returned to it several times in short fiction. The stories move across wildly different versions of Earth, from worlds where Rome never fell to timelines stuck in the Stone Age. Lord Kalvan of Otherwhen, the longest and most developed Paratime story, was published as a novel in 1965 after Piper’s death. John F. Carr later wrote continuation novels expanding the Paratime universe.