STORIES of the development of new drugs and other medical
advances often are told as if logic had dictated every step, as
if the researchers had known from the beginning what they were
looking for and exactly how to find it. In fact, the development
of new drugs is a much more complicated process than some res
earchers would have the public believe, and the new drugs that
appear each year reach the market by many more paths than we
realize.  Clearly some developments do reflect logical
deductions from planned research. But the development process
also involves such nonscientific factors, as perseverance and
luck. Researchers have discovered new therapies, for example,
by: drawing new conclusions from accidental findings; paying
attention to the observations of patients; turning unwanted side
effects into something of value, and finding new uses for old
drugs.  Now, in one of the most unusual stories in the annals of
pharmacology, a drug marketed for one purpose - and removed from
the market because it was too