Foreword——————————————————- SGML is misunderstood and underestimated. I have always wanted to write this book. I am pleased that two people with whom I have had the pleasure to work were finally able to do so. Since I have always been a bit of an evangelist, I feel pride when my "students" become recognized "teachers". In the early years of SGML we struggled to define a language that would bring the information to its rightful place. We succeeded. Then we had to explain these idea to technical adoptors. Again, I think we have succeeded. We have learned much about SGML in the process of implementing it. These experiences must now also be shared, along with comprehensible information on the language itself. The word must move out of the lab and the computer center and reach the business people, the users, the movers and shakers. The next generation will do things with SGML that we can't even imagine yet- it is that versatile.