Stardeath — E.C. Tubb

Ships occasionally disappeared in hyperspace, regrettable sacrifices to the luxury of faster than light travel. But now one of the lost ships has been found and the wreckage is enough to terrify even the most cold-blooded witness.

The lucky ones on the lost ship are dead. The others have been turned inside-out in gruesome parody of human beings and they are still alive.
Disgraced Captain Kurt Varl is chosen to command a suicide mission to discover the cause of these disasters.

The enemy is unknown and the only way Varl can solve the mystery is to use himself as bait!