Writing this book has been a happy task. It deals with a very serious problem, with a very happy ending. It would be hard to think of anything more rewarding for this effort than the knowledge that we can begin the task of breast-cancer prevention --- now.

          People have often asked me to write a book which has no numbers, no mathematics, no symbols, no equations. I appreciate their fear that they will not understand. We, who have worked on the preparation of this book, think that anyone can understand the fascinating past history of 100 years of the x-ray in the production of breast-cancer.

          Simply accept "numbers" the first time through. The story will tell itself that way. And then come back, if you are so inclined, to challenge all the numbers. The numbers are your insurance that this story has real legs.

          Three people have made exceedingly large contributions to the book. Many improvements in the writing come from them. Professor Helen Gofman patiently brought the perspective of a pediatrician and a general physician as she meticulously went through the manuscript to tell me where it would not be understood without changes.

          Egan O'Connor, our Editor of CNR Books, not only put a rough manuscript into the English language, but provided a clear, cool, critical head in challenging everything placed before her.

          John David Gofman, M.D., my son, volunteered to "look the manuscript over," and indeed he did. All the pages, and all the lines. His insights, his advice, his knowledge made a very large difference in the final book which evolved through his and Egan's critical comments and contributions to ideas and style.

          Lastly, there is one special place in my heart, for an assist which was absolutely essential. That place is occupied by the superb library of our medical school at the University of California in San Francisco. What a treasure --- a collection so rich as to make the trip back through 100 years of medicine an easy one. And the cooperation of the librarians was superb.

          This is the beginning of an effort to prevent cancer in one effective manner. Most of the methodology will be applicable for an effort with cancers other than those of the breast. Indeed, we hope other investigators will make their own studies using such methods as are presented. For the inevitable errors and unclear passages, I take all the credit. We shall try to improve later editions as we learn of such flaws.

John W. Gofman, M.D., Ph.D.          
San Francisco, California                  
Spring 1995.