Introduction / Groff Conklin -- Elsewhen: Shortstack / Walt and Leigh Richmond. How allied / Mark Clifton. The wrong world / J.T. McIntosh. World in a bottle / Allen Kim Lang -- Elsewhere: Think blue, count two / Cordwainer Smith. Turning point / Poul Anderson. The book / Michael Shaara. Trouble tide / James H. Schmitz. The Earthman's burden / Donald E. Westlake.