The listing, ASSIGNMENT NOR'DYREN by Sidney Van Scyoc has ended.
Paperback, doesnt look like its been read..I'm pretty sure it's a first edition. published in 1973, It's the only date listed on the info page. front cover, top, 'AVON SCIENCE FICTION /17160/75C(ents).
Save the planet! Once, Nor'Dyren had been a planet ruled by technology and progress. Now, it was primitive, sinking into poverty and despair, and it was Earthman Tollan Bailey's mission to find out why.
His investigation was just the beginning of an amazing adventure into the past...and a grim battle against sinister political forces dedicated to preventing change at any cost. Could Bailey save the planet from oblivion? And could he save himself?