@Wine. Are you sure you are talking about the novel, “Phantom of the Opera” rather than the musical? I know of no one who has read it, even among the most voracious readers.
“The Phantom of the Opera (French: Le Fantôme de l’Opéra) is a novel by French writer Gaston Leroux. It was first published as a serialisation in Le Gaulois from September 23, 1909 to January 8, 1910.
Initially, the story sold very poorly upon publication in book form and was even out of print several times during the twentieth century; it is overshadowed by the success of its various film and stage adaptations.
The most notable of these were the 1925 film depiction, Ken Hill’s 1976 musical at the Theatre Royal Stratford East followed ten years later by Andrew Lloyd Webber’s 1986 musical that in turn inspired the 2004 film adaptation directed by Joel Schumacher.” Source