  Liquid $^3$He confined in low-density, highly porous random solids such as
silica aerogel provides tuneable systems to study the effects of disorder and
confinement on the properties of a quantum liquid. New superfluid phases result
from the interplay between disorder, confinement and complex symmetry-breaking.
An extended bibliography is appended. An edited and abbreviated version of this
article appeared in Physics Today 71, 11, 30 (2018).
