Rayleigh-Bénard convection and turbulence in liquid helium

Recent advances in the understanding of Rayleigh-B\'enard convection and turbulence are reviewed in light of work using liquid helium. The discussion includes both experiments which have probed the steady flows preceding time dependence and experiments which have been directed toward understanding the ways in which turbulence evolves. Comparison is made where appropriate to the many important contributions which have been obtained using room-temperature fluids, and a discussion is given explaining the advantages of cryogenic techniques. Brief reviews are given for recent experimental investigations of convection in ³He-⁴He mixtures---in both the superfluid and the normal states---and investigations of convection in rotating layers of liquid helium.