We model the propagation of three-dimensional, adiabatic, linear Alfv¿n waves in the solar atmosphere and wind, taking into account relevant physical effects, including gravity stratification, thermal conduction, radiative losses, and heating (via a phenomenological term). Our magnetohydrodynamic solar wind model also accounts for the momentum deposition by a spectrum of non-WKB Alfv¿n waves. The transmission and reflection of such waves has been previously studied by a variety of techniques, including calculations based on the computation of the ratio between the wavelength and the scale length of the Alfv¿n speed change and based on a globally-computed transmission coefficient. In this paper we discuss both techniques and show how they are related. We also discuss the physics underlying the reflection process and the possible role wave reflection might play in the acceleration of the solar wind and the winds from other stars. ¿ American Geophysical Union 1996