"Fangirl" is a young adult novel by Rainbow Rowell that was published in 2013. The book follows the story of Cath, a socially awkward freshman in college who is a passionate fanfiction writer. As Cath navigates the challenges of college life, she also struggles with her changing relationships with her twin sister Wren, her father, and her love interests. Along the way, she must confront her anxiety, her fears of abandonment, and her reluctance to embrace change. Through her experiences, Cath learns the importance of finding her own voice and standing up for herself, both as a writer and as a person. "Fangirl" is known for its relatable characters, its honest portrayal of mental health issues, and its exploration of the power of fandom and creativity. It has been widely praised for its humor, heart, and authenticity, and has become a beloved classic of contemporary young adult literature.