  Nearly 4 years ago, two teams of observational astronomers reported that
high-redshift Type Ia supernovae are fainter than expected in a decelerating or
freely coasting universe. The radical conclusion that the universe has been
accelerating in the past few billion years, possibly because of a nonzero value
for Einstein's cosmological constant, has gripped the worlds of astronomy and
physics, causing a flurry of new research. Having participated on both teams
(but much more closely with one than the other), here I provide a personal,
historical account of the story.
