  We review recent progress in utilizing ultrafast light-matter interaction to
control the macroscopic properties of quantum materials. Particular emphasis is
placed on photoinduced phenomena that do not result from ultrafast heating
effects but rather emerge from microscopic processes that are inherently
nonthermal in nature. Many of these processes can be described as transient
modifications to the free-energy landscape resulting from the redistribution of
quasiparticle populations, the dynamical modification of coupling strengths and
the resonant driving of the crystal lattice. Other pathways result from the
coherent dressing of a material's quantum states by the light field. We discuss
a selection of recently discovered effects leveraging these mechanisms, as well
as the technological advances that led to their discovery. A road map for how
the field can harness these nonthermal pathways to create new functionalities
is presented.
