Gas-liquid direct-contact evaporators are characterized by the bubbling of a superheated gas through the solution to be concentrated. In other words, they are nonisothermal bubble columns. Despite their simplicity of construction, these units exhibit rather complex hydrodynamics and, similar to what occurs to isothermal bubble columns, the design of such units still poses a problem. The present paper reviews the literature regarding this kind of equipment, addressing both experimental studies and modeling efforts. The covered issues include classic and potential applications, bubbling regimes, gas holdup and bubble size distributions, as well as mathematical models proposed for simulating the unit. Additionally, pertinent literature on isothermal bubble columns is also discussed. Recommendations are made for future research.