Notes: • "Berkley Edition, December, 1955" • Printing not stated, no number line • In the back of the book there is an ad for a non-genre publication: More Sweetie Pie by Nadine Seltzer which was published in 1957. The printing history from the 7th Berkley printing has the second printing as November 1957. • Other than the ads, the only difference from the first printing is the absence of the letters ANC above the price on the cover. • "This book is based upon previously published stories By A. E. van Vogt: "Concealment" and "The Storm," copyright © 1943, by Street and Smith Publications, Inc., and "The Mixed Men," copyright © 1945, by Street and Smith Publications, Inc." stated on the copyright page. • Printed in the US • The cover is credited to Powers on the copyright page