I literally owe my career to this book. If there were only one AS/400 sys admin book you could own, this would be the one! Two years ago I was thrown into the fires of AS/400 System administration. This book was the water I needed to put out those fires and become a proactive system administrator. It sits on the corner of my desk and I still reference it all the time. The "Primer" explains the situation in simple enough terms that a beginner will become excited about setting up and working with the AS/400. Then it will take you to the next level so that you can become a proactive administrator rather than a reactive one. I have recommend the "Primer" to friends that are seasoned administrators and they reference it all the time too. I just can't say enough about this book.