First paperback edition of
The Wanderer, by Fritz Leiber (Ballantine, 1964). A wild novel following the events that transpire after a "wandering" planet enters the Solar System, the story includes telepathic feline humanoids and a criminal trial for the wandering planet. The novel won the Hugo Award in 1965, the first book to do so after being initially published in paperback form.
This book is in very good condition, with a very small (0.25") tear to the top of the front cover, but with no other major signs of wear.