 The modern idea of the multiverse is theologically more controversial. In its so-called landscape version, which since 2002 has been promoted and developed by Leonard Susskind and many other physicists, it is based on the apparent non-uniqueness of the equations of string theory. The solutions of the equations describe, in a sense, possible worlds with different physical parameters, interactions, types of particles, and even dimensionality; the multitude of solutions are then identified with really existing worlds which generally are causally separate from ours. As a mechanism for generating the huge number of universes, multiverse physicists make use of the eternal inflation scenario. Moreover, the multiverse is closely associated with anthropic reasoning: we find ourselves in our universe, with its particular physical laws and content of particles, not because other universes are impossible or improbable, but because our kind of life cannot exist in other universes. The theory of the multiverse has seductively great explanatory power (while it has almost no predictive power), which is a major reason why many physicists and cosmologists find it attractive. On the other hand, other physicists dismiss it as pseudoscience because it is practically untestable.