As I reflect on the evolution of this book, I am struck by the differences be tween my early conceptions and the final product. When I was first ap proached by Springer-Verlag regarding a monograph on my interests in the area of fetal lung development, I imagined that it would be relatively easy to summarize my contributions, plus the work of other investigators as needed for proper perspective. This rather naive idea was abandoned as I prepared my initial outlines for the monograph. I quickly realized that con tributions from my laboratory are not sufficient for telling the story of...