The hydrologic mechanisms underlying the climate-soil-vegetation dynamics and thus controlling the most basic ecologic patterns and processes are described as one very exciting research frontier for the years to come. In this personal opinion I have concentrated on those processes where soil moisture is the key link between climate fluctuations and vegetation dynamics in space and time. The soil moisture balance equation at a site is shown to be the keystone of numerous fundamental questions which may be instrumental in the quantitative linkage between hydrologic dynamics and ecological patterns and processes. Some of those questions are outlined here, and possible avenues of attack are suggested. The space-time links between climate, soil, and vegetation are also explored from the hydrologic perspective, and some exciting research perspectives are outlined. ¿ 2000 American Geophysical Union