A review is given on Brillouin-scattering measurements taken in the vicinity of liquid-solid interfaces with a variety of ratios of acoustic impedances. For this purpose we have taken ethanol, polycarbonate and the liquid metals mercury and gallium in close contact with solid glass substrates. Some refined measurements on Lamb and Love modes in thin polycarbonate films on Pyrex glass are reported. A Stoneley-type wave at the liquid metal-glass interface is analysed in some detail. Our improved double-pass tandem Fabry-Pérot interferometer is described briefly