By 
The Entropy Effect by Vonda N. McIntyreThe U.S.S. Enterprise is summoned to transport a dangerous criminal from Starbase prison to a rehabilitation center, the brilliant physicist Dr. Georges Mordreaux, accused of promising to send people back in time, and then killing them instead.
But there’s more at stake than just a few lives. For Mordreaux’s experiments have somehow thrown the entire universe into a deadly time warp. All of existence is closing in on itself, and only Spock can stop the Entropy Effect.
