  Inaccurate modelling of the near-surface layers of solar models causes a
systematic difference between modelled and observed solar mode frequencies.
This difference---known as the "surface effect" or "surface term"---presumably
also exists in other solar-like oscillators and must somehow be corrected to
accurately relate mode frequencies to stellar model parameters. After briefly
describing the various potential causes of surface effects, I will review
recent progress along two different lines. First, various methods have been
proposed for removing the surface effect from the mode frequencies and thereby
fitting stellar models without the disproportionate influence of the inaccurate
near-surface layers. Second, three-dimensional radiation hydrodynamics
simulations are now being used to replace the near-surface layers of stellar
models across a range of spectral types, leading to predictions of how some
components of the surface effect vary between stars. Finally, I shall briefly
discuss the future of the problem in terms of both modelling and observation.
