  The demand for sophisticated tools and approaches in heat management and
control has triggered fast development of emerging fields including conductive
thermal metamaterials, nanophononics, far-field and near-field radiative
thermal management, etc. In this review, we cast a unified perspective on the
control of heat transfer, based on which the related studies can be considered
as complementary paradigms toward manipulating physical parameters and
realizing unprecedented phenomena in heat transfer using artificial structures,
such as thermal conductivity in heat conduction, thermal emissivity in
radiation, and properties related to multi-physical effects. The review is
divided into three parts that focus on the three main categories of heat flow
control, respectively. Thermal conduction and radiation are emphasized in the
first and second parts at both macro- and micro-scale. The third part discusses
the efforts to actively introduce heat sources or tune the material parameters
with multi-physical effects in both conduction and radiation, including works
using thermal convection. We conclude the review with challenges in this
research topic and new possibilities about topological thermal effects, heat
waves, and quantum thermal effects.
