Entropy was a science fiction fanzine by Terry Carr.
The first issue of Entropy appeared in November 1964, published in Brooklyn, New York, U.S.A. It was an 8 1/2 by 11 inch fanzine of 26 pages.
Entropy was dedicated to reprinting work by fanzine writers that had appeared in older fanzines (not necessarily their own fanzines), and combining them with newer illustrations.
Reprints included Mal Ashworth, from Brennschluss; Jack Darrow, from The Fourteen Leaflet; Dave English, from Fiendetta; Dean Grennell, from Contour; Walt Liebscher, from A Bas; Bob Tucker, from Oopsla; and Sam Youd, from Fission.