This is one of the less common paperbacks. While it is only moderately
difficult to locate, the price is relatively high, especially if the book is in
good shape, has no bookstore stamps and especially if the cigarette ads are
still in the middle of the book. Bindings were very bad on this title so if you
have a copy with the binding fully intact it will highly increase the value. It
is an expanded version of his novella "A Third Hand", which was originally
The Magazine of Fantasy and Science Fiction
in January 1970.
You have a first edition of this paperback if you own a copy as there was only
one printing as far as I have seen.