* The historical figure Giacomo Casanova: He was a real person, an 18th-century Italian adventurer, spy, and writer. He didn't write a single book titled "Casanova," but he did write his autobiography, "Histoire de ma vie" (Story of My Life), which is a primary source for understanding his life and exploits.
* The fictional character Casanova: This character has been popular in literature, theatre, and film for centuries. Many authors have used Casanova as inspiration, and his story has been adapted and reimagined countless times.
* The play "Casanova" by Michael Frayn: This play was first performed in 1979 and is a fictionalized account of Casanova's life.
So, to answer your question definitively, it depends on what "Casanova" you're referring to.
* Giacomo Casanova himself wrote his autobiography, "Histoire de ma vie."
* Many authors have written about Casanova, but none of them wrote a single book titled "Casanova."
* The play "Casanova" was written by Michael Frayn.
Let me know if you have a specific "Casanova" in mind, and I can help you find more information!