  The importance of understanding the current and historical galactic
environments of cool stars is discussed. The penetration of interstellar gas
into a stellar astrosphere is a function of the interaction of the star with
the interstellar cloud surrounding the star, and this factor needs to be
understood if an efficient search for life-bearing planets is to be made. For
the Sun, both current and historical galactic conditions are such that if a
solar wind were present, it would have excluded most inflowing interstellar
matter from the inner regions of the heliosphere for the past few million
years. Variations in heliosphere size over the recent historical path of the
Sun are estimated, along with estimates of astrosphere sizes for selected
nearby stars. Considering only possible effects due to encounters with
interstellar clouds, stable planetary climates are more likely for inner than
outer planets.
