SEYMOUR Martin Lipset and Gary Marks’ It Didn’t Happen Here: Why Socialism Failed in the United States † represents Lipset’s most recent and most substantial entry in his 50-year effort to understand why socialism made no great impact in the United States, while it succeeded—in the sense of creating mass parties with opportunities to govern—in the other major industrial societies. (Since I will consider this book in the context of Professor Lipset’s involvement with this problem through his entire professional life, I hope Gary Marks will forgive me for using the shorthand of referring to the book as Lipset’s, with the understanding that Marks is a full co-author.)