Dr. Carl Sagan, the David Duncan Professor of Astronomy and Space Sciences and director of the Laboratory for Planetary Studies at Cornell University, has returned for diagnosis and treatment to the Fred Hutchinson Cancer Research Center in Seattle. During careful post-treatment monitoring, the earliest signs of a potential relapse of myelodysplasia were detected. It is being vigorously treated with the objective of a complete cure. Dr. Sagan is continuing his research and writing schedule and expects to be back at Cornell University in the fall.