Instruct: Classify Amazon reviews into positive or negative sentiment
Query: John A Henderson MD

The cover describes this history of hypnotism as, "by Peter Reveen as told to William Harwood." That seems like a strange collaboration. Reveen was a concert hypnotist whose bread and butter depended on convincing his audiences, including the book's purchasers, that the performers on his stage were really hypnotized. But historian Harwood is on record elsewhere as concluding that, "Hypnotism has never been demonstrated to exist and almost certainly does not exist." Not surprisingly, the book endorses the sincerity of pioneers like Anton Mesmer and James Braid, but without making claims with which the book's editor could not associate his name. Did Reveen believe in hypnotism when the book was written? Probably. Does he still believe in hypnotism? Even Harwood cannot answer tht one.