Which novel by E.L. James started as a fanfiction before becoming a global publishing phenomenon, exploring a complex and erotic relationship?

Fifty Shades of Grey

"Fifty Shades of Grey" began modestly on fanfiction forums before capturing the attention and imagination of the public on an unexpected scale. The novel sparked lively debates on themes of dominance and submission in romantic relationships, becoming a global conversation topic. Its success led to two sequels and a series of films, significantly broadening its cultural impact. The enduring fascination with the story of Christian Grey and Anastasia Steele reflects the public's curiosity and interest in exploring complex relationship dynamics.