Superheroes and supervillains, and figures in many science fiction novels, etc commonly use telepathy. Notable telepaths include Lwaxana Troi of Star Trek: The Next Generation; Lyta Alexander, Alfred Bester, and the rest of the Psi Corps of Babylon 5; Dr. Wendy Smith of seaQuest DSV; and Charles Xavier, Jean Grey, Psylocke and Emma Frost of X-Men.The mechanics of telepathy in fiction vary widely. Some fictional telepaths are limited to receiving only thoughts that are deliberately sent by other telepaths, or even to receiving thoughts from a specific other person. For example, in Robert A. Heinlein's 1956 novel Time for the Stars, certain pairs of twins are able to send telepathic messages to each other. Some telepaths can read the thoughts only of those they touch. At the opposite end of the spectrum, some telepathic characters continuously sense the thoughts of those around them and may control this ability only with difficulty, or not at all. In such cases, telepathy is often portrayed as a mixed blessing or as a curse.Some fictional telepaths possess mind control abilities, which can include "pushing" thoughts, feelings, or hallucinatory visions into the mind of another person, or completely taking over another person's mind and body (similar to spiritual possession). Characters with this ability may or may not also have the ability to read thoughts.