The interaction of a plane electromagnetic wave with a flat free-space – plasma interface has been considered for arbitrary angles of incidence. It is shown that the plasma can support independent horizontally and vertically polarized waves. Expressions and graphical representations are given showing the amount of energy entering the plasma as a function of angle of incidence and plasma parameters. The vertically polarized case shows a maximum in the energy entering the plasma at the "Brewster angle". For a lossy plasma, at this maximum, there will be reflection. Loci of constant Brewster angle appear as concentric curves centered on the origin of the complex dielectric coefficient plane.The elliptical polarization of a plane wave reflected from the interface, when a wave with equal horizontally and vertically polarized components is incident on the interface, suggests the similarity of lossless plasmas to ordinary dielectrics and of lossy plasmas to metals.