Complex sentence: The Illuminati are often illustrated in famous novels, such as the "Illiminatus" trilogy by Robert Shea and Robert Anton Wilson, in "Foucault's Pendulum" by Umberto Eco or in "Angels and Demons" by Dan Brown.
Split into simpler sentences: The Illuminati are often illustrated in famous novels, such as the Illuminatus! Trilogy by Robert Shea and Robert Anton Wilson; in "Foucault's Pendulum" by Umberto Eco; or "Angels and Demons" by Dan Brown.