Ingram Because of the deadly "effect sphere," the only way into or out of the system containing the metal-rich Ring Mines of Solitaire is by performing a human sacrifice. Now every ship heading there carries two death-row felons. It's a bizarre, but effective method of execution--until it's discovered that one of the doomed criminals is an innocent man.
Used availability for Timothy Zahn's Deadman Switch
October 1988 : USA Paperback
October 2012 : USA, Canada, UK Kindle edition