  This work reviews basic features of both Rayleigh-B\'enard (RB) convection
and internally heated (IH) convection, along with findings on IH convection
from laboratory experiments and numerical simulations. In the first chapter,
six canonical models of convection are described: three configurations of IH
convection driven by constant and uniform volumetric heating, and three
configurations of RB convection driven by the boundary conditions. The IH
models are distinguished by differing pairs of thermal boundary conditions: top
and bottom boundaries of equal temperature, an insulating bottom with heat flux
fixed at the top, and an insulating bottom with temperature fixed at the top.
The RB models also are distinguished by whether temperatures or heat fluxes are
fixed at the top and bottom boundaries. Integral quantities important to heat
transport are discussed, including the mean fluid temperature, the mean
temperature difference between the boundaries, and the mean convective heat
transport. Integral relations and bounds are presented, and further bounds are
conjectured for the IH cases. The second chapter presents results that can be
derived mathematically from the governing equations: linear and nonlinear
stability thresholds of static states, and parameter-dependent bounds. Known
bounds are on mean temperatures in IH convection and on convective transport in
RB convection. The third chapter reviews numerical simulations and laboratory
experiments on IH convection, emphasizing quantitative results.
