How did adaptations of films and books become stage musicals?

Adaptations of films and books have long served as a foundation for stage musicals, as creators frequently look to established literature and drama to provide potent narratives. By transforming familiar stories into musical theatre, producers can leverage existing audience recognition while using music to create the "illusion" that defines the genre.1

The process of adaptation often involves distilling complex narratives into a cohesive whole where songs, dialogue, and dance are integrated to advance the plot. Notable examples of this practice include:21

• Classical Literature: Works such as Romeo and Juliet were transformed into West Side Story, and Oliver Twist became the musical Oliver!.1
• Film Adaptations: In the late 20th and 21st centuries, many films were adapted for the stage, including The Lion King, The Producers, and Legally Blonde.32
• Historical Figures: Some musicals, such as Hamilton, adapt historical biographies into musical narratives.32

These adaptations are often driven by economic considerations, as successful source material can help ensure the long runs necessary to recover the high costs of modern theatrical productions.21