The "Psy-Changeling" series, written by Nalini Singh, is a popular paranormal romance collection set in a world where three distinct groups coexist: the Psy, the Changelings, and humans. The Psy are a telepathic race that suppresses emotions, while the Changelings are shapeshifters who embrace their animal instincts. This unique setting allows for rich character development and exploration of themes like love, identity, and the struggle between emotion and control. Throughout the series, various characters navigate their relationships and conflicts, often facing challenges that arise from their differing natures. The books blend romance, suspense, and fantasy elements, appealing to fans of both romance and speculative fiction. Each installment typically focuses on a different couple, while also contributing to an overarching narrative about the balance of power among the three groups.