xvii and did the other thing that made Unix so very successful: give it away to all the universities of the world. I have to admit to a deep love-hate relationship with Unix. Much though I try to escape it, it keeps following me. And I truly do miss the ability (actu- ally, the necessity) to write long, exotic command strings, with mysterious, inconsistent flag settings, pipes, filters, and redirections. The continuing popularity of Unix remains a great puzzle, even though we all know that it is not the best technology that necessarily wins the battle. I’m tempted to say that the authors of this book share a similar love-hate relationship, but when I tried to say so (in a draft of this foreword), I got shot down: “Sure, we love your foreword,” they told me, but “The only truly irksome part is the ‘c’mon, you really love it.’ No. Really. We really do hate it. And don’t give me that ‘you deny it—y’see, that proves it’ stuff.” I remain suspicious: would anyone have spent this much time and effort writing about how much they hated Unix if they didn’t secretly love it? I’ll leave that to the readers to judge, but in the end, it really doesn’t matter: If this book doesn’t kill Unix, nothing will. As for me? I switched to the Mac. No more grep, no more piping, no more SED scripts. Just a simple, elegant life: “Your application has unexpect- edly quit due to error number –1. OK?” Donald A. Norman Apple Fellow Apple Computer, Inc. And while I’m at it: Professor of Cognitive Science, Emeritus University of California, San Diego