The Three Stigmata of Palmer Eldritch - Philip K Dick

In the overcrowded world and cramped space colonies of the late 21st century, tedium can be endured through the use of the drug Can-D, which enables the user to inhabit a shared illusory world. When industrialist Palmer Eldritch returns from an interstellar trip, he brings with him a new drug, Chew-Z, which is far more potent than Can-D, but threatens to plunge the world into a permanent state of drugged illusion controlled by the mysterious Eldritch.