Phantom, the musical and 1990 miniseries "The Phantom of the Opera" are based on the 1910 novel by which author?
The Phantom of the Opera (miniseries):  It is adapted from Arthur Kopit's book for his then-unproduced stage musical "Phantom", which is based loosely on Gaston Leroux's novel. Phantom (musical): Phantom is a musical with music and lyrics by Maury Yeston and a book by Arthur Kopit.
i don't know