  The NASA Dawn spacecraft took off from Cape Canaveral in September 2007 atop
a Delta II rocket starting an ambitious journey to Vesta and Ceres, the two
most massive worlds in the largest reservoir of asteroids in the Solar System,
the Main Belt. Prior to the Dawn launch, Earth-bound observations of Vesta and
Ceres revealed intriguing features--from Vesta's rugged shape to Ceres' tenuous
water exosphere--, but these objects remained fuzzy speckles of light even
through the lenses of the most powerful telescopes. With Dawn's exploration of
Vesta (2011-2012) and Ceres (2015-2018) these two worlds came into focus.
Breath-taking details emerged of how large collisions sculpted Vesta liberating
massive amounts of material in the inner Main Belt, providing the source of an
important family of meteorites recovered on Earth. Ceres' complex geology,
which may rival that of the Earth and Mars, unveiled recent cryovolcanic
activity. This book is dedicated to these highlights, and many more discoveries
of the Dawn mission. By the time Dawn completed its mission in 2018, our
understanding of the formation of the Solar System had greatly evolved thanks
to new theoretical models and to a new trove of meteorite geochemical data, and
Dawn observations of Vesta and Ceres provide new, vital constraints to
synergistically interpret models and data. The broader implications of the Dawn
legacy are presented in a series of dedicated chapters. The editors hope this
book will serve as a solid reference for the younger generations as well as for
more seasoned researchers to successfully pursue future exploration of the Main
Belt. We certainly have learned a lot thanks to Dawn, and yet we know that we
have barely scratched the surface of what Main Belt asteroids can tell us about
the dawn of our Solar System.
