Yasutaka Tsutsui
"Paprika" (1993) by Yasutaka Tsutsui is a science fiction novel that involves entering dream worlds using technology. In the book, dream monitoring and intervention as a means of treating mental disorders is a developing new form of psychotherapy in the near future. Unrest ensues when a new psychotherapy dream-analysis device is stolen, allowing the assailant to enter and manipulate people's dreams.