Perilous Planets: An Anthology of Way Back When Futures by Brian W. Aldiss, C.C. Shackleton, E.C. Tubb, Cordwainer Smith, P. Schuyler Miller, Damon Knight, Norman Spinrad, Frederik Pohl, Robert Silverberg, David I. Masson, Alan E. Nourse, A.E. van Vogt, Robert Sheckley, Michael Shaara, Clifford D. Simak, Cherry Wilder, Robert F. Young