The discovery of a significant number of extrasolar planets in double-star systems has sparked interest in whether such environments could support habitable worlds. Research has shown that the presence of a second source of radiation as well as additional gravitational interactions can influence the location and extent of circumstellar and circumbinary habitable zones. In this chapter, several concepts are revisited that can guide our expectations on where terrestrial planets might retain liquid water in multistellar environments. Isophote-based, radiative, and dynamically informed habitable zones are discussed and compared to self-consistent modeling results. Simple analytic expressions for the size of circumstellar and circumbinary habitable zones are presented which primarily depend on stellar parameters, but also on a planet’s atmospheric and surface composition, its climate inertia, and its orbital dynamics. The higher the resilience to variations in the incident light, the higher the chances for a planet to remain in a habitable state. In systems like \(\alpha \) Centauri, habitable zones can shrink by up to 50% depending on the climate inertia of terrestrial worlds. For circumbinary planets, the mass ratio of the stars and their distance to the habitable zone determine the impact of climate inertia on planetary habitability. Systems with similar stellar components such as Kepler-35 turn out to be excellent places to search for potentially habitable worlds.