The Man in the Maze published 1971 - Good condition, cover has some shelf wear, a sticker or two to front that someone has has coloured in. Pages usual age tan, with some spotting at front also,

The Time Hoppers Published 1970 - Good condition, cover has some marks and shelf wear. Can see someone has put pen on this as well, they've got a bit handy with a black marker, not so obvious but I have tried to show in last 2 images. Just marking on the black part of cover. Pages usual age tan.

Lots more science fiction on my eBay :)