Frank Landis: 2 books

Kane Azeka wakes up inside the head of teenaged Dana Hallis, told to record Dana’s memories by a mysterious being. He and Dana have to survive, together, on the alien moon Nysus, where the wildlife thinks industrial materials are delicious, unprotected machines rot quickly in the lowland jungles, and the human colonists destroy scions like Kane whenever they find them.

A consultant finds a fossilized pack in the desert, then finds himself back in the Miocene with a criminal gang. A game warden busts a group of trespassing druids in a wildlife sanctuary. They vanish in a green flash and he loses his job, only to be recruited for something much bigger. This...