Roots by Alex Haley is highly controversial because the author marketed it as a meticulously researched, non-fiction genealogy, but it was later revealed to contain extensive fabrications, historical inaccuracies, and plagiarism.

The controversy stems from several major issues:

Plagiarism: Haley was sued by author Harold Courlander for lifting significant portions of his 1967 novel, The African. Haley settled out of court for $650,000 and admitted to using passages from the book.

Fabricated Genealogy: Investigations revealed that Haley's reported ancestral link to the village of Juffureh and his famous ancestor, Kunta Kinte, lacked documentary evidence. The oral traditions he relied on were largely debunked as inaccurate or tailored to what Haley wanted to hear.

Historical Inaccuracies: Historians and genealogists, such as Elizabeth Shown Mills and Gary B. Mills, found numerous geographical, historical, and factual inconsistencies throughout the timeline of his family's saga.

Blurred Genre Lines: Although the book was originally presented as absolute fact, experts realized it was closer to an autobiographical novel. Haley himself coined the term "faction" (fact plus fiction) to describe it, but this did not stop critics from condemning the deception.

Despite the controversy, Roots is still widely recognized for its cultural impact and for bringing the brutal realities of the transatlantic slave trade into mainstream American consciousness.