Scenario-based investigations of possible futures have been used since the middle of the 20th century to help decisionmakers cope with alternative courses of action and elements of uncertainty. Since the early 1970s, they have been increasingly used for landscape planning. Each scenario-based study is founded on assumptions of possible change. Often these beliefs are only implicit among scenario creators and scenario users. I discuss the beliefs and perceptions about the future of scenario creators and scenario users, and argue that they should be explicitly addressed before an investigation is undertaken in order to avoid methodological biases in the creation of the scenarios and misunderstanding of the results. As part of this discussion, the basic features of a scenario-based study are reviewed, and applications to landscape and environmental planning are considered, with examples drawn from two studies that were focused on the same concerns and in the same region but which employed different kinds of scenarios.