The Door through Space

An agent of Terran Intelligence on the planet Wolf is being transferred to Vainwal when he's dragged off the starship and sent out on a mission which proves to be a series of complicated traps, set by multiple enemies--some of whom have mistaken him for someone else entirely.

Note: This is Marion Zimmer Bradley's first published novel, a precursor to the Darkover series. Foreword by Elisabeth Waters.