I remember buying 30 Science Fiction books from a co-worker 37 years ago for $9. Tunnel in the Sky was one of the books and 'I still have it.' Out of all the things I have aquired and parted with, these books seemed to always remain with me. Hearing you mention it make me think I will get it out and read it again. Excellent storyline as I remember. Never thought of it as a survival book back then. "Beware of the stober"
Thanks, Bill