The invisible enemy, by Jerry Sohl 79645 [Author: Jerry Sohl] [Illustrator: Harold W. McCauley] [Illustrator: Lloyd Rognan] [Link: https://www.gutenberg.org/ebooks/79645] note: link will be active within two hours of posting. Thanks to Tom Trussel - Stories of Futures Past (This file was produced from images generously made available by The Internet Archive). Regards, Robert