  We present a review of the state-of-the-art of our understanding of the
intrinsic charm and bottom content of the nucleon. We discuss theoretical
calculations, constraints from global analyses, and collider observables
sensitive to the intrinsic heavy quark distributions. A particular emphasis is
put on the potential of a high-energy and high-luminosity fixed target
experiment using the LHC beams (AFTER@LHC) to search for intrinsic charm.
