I FIRST MET JIM SIRE more than fifty years ago. I was a twenty-one-year-old college student, attending an InterVarsity National Leadership Institute at Cedar Campus in Michigan’s Upper Peninsula. Jim was the newly appointed, first full-time editor of InterVarsity Press. I found him warm and engaging with a self-deprecating, if often impish and provocative, sense of humor. Bright and inquisitive, he seemed just the right person to launch a new era in Christian publishing with the university and the world as its purview.

Little did I imagine then that ten years later he would invite me to join the editorial staff of the Press. By then the first edition of The Universe Next Door had already established itself as a key book for the intellectually curious looking to explore how Christianity fit within the swirl of worldviews on university campuses. The book itself, as Jim notes, grew from a series of lectures that he gave over several summers at the Christian Study Project. I spent a few days sitting in on the lectures in the summer of 1979. Soon thereafter I became Jim’s primary in-house editor, working not only on revisions of The Universe Next Door, but also on most of his subsequent books: Scripture Twisting, Discipleship of the Mind, Chris Chrisman Goes to College, Why Should Anyone Believe Anything at All?, Habits of the Mind, Naming the Elephant, Why Good Arguments Often Fail, and A Little Primer on Humble Apologetics. We spent many a lunch hour together and with others exploring Jim’s ideas on these and many other topics.

So I was honored when the editorial staff invited me to work on this sixth edition. Had Jim not already done most of the work on the revisions prior to his untimely death in February 2018, I wouldn’t have attempted it—I’ve neither taught nor researched the material independently—though years of friendship have helped me to think Jim’s thoughts after him. Most of Jim’s additions will be found at the end of the book where an additional chapter, “Building a Christian Worldview for the Twenty-First Century: A Work in Progress,” and an appendix containing several helpful diagrams and thumbnail sketches may be found.

I have expanded the number of sidebars that offer helpful definitions and reflections along the way, and I have added updated references at various points, some of which came directly from Jim and others that came from outside reviewers—namely, Tawa J. Anderson, Robert Lively, and J. Mark Bertrand. While unable to implement all their helpful suggestions, I am grateful for the feedback these readers offered. Previous users will note that instead of just referencing the worldview questions by number as they come up in each chapter, I have added a brief parenthetical word or two to trigger the reader’s memory of the issue involved. Each chapter now includes questions for reflection and discussion that should add to comprehension of the material.

I hope this new edition will serve a new generation of readers seeking to live out an examined life under the Lordship of Jesus Christ.