An asteroid family is typically formed when a larger parent body undergoes a
catastrophic collisional disruption, and as such family members are expected to
show physical properties that closely trace the composition and mineralogical
evolution of the parent. Recently a number of new datasets have been released
that probe the physical properties of a large number of asteroids, many of
which are members of identified families. We review these data sets and the
composite properties of asteroid families derived from this plethora of new
data. We also discuss the limitations of the current data, and the open
questions in the field.Comment: Chapter to appear in the Space Science Series Book: Asteroids I