Ultimate Invitations What Is The Meaning In Nabokov's Invitation To A Beheading?

What is the meaning in Nabokov's Invitation to a Beheading? - ultimate invitations

This question is for those who read the Invitation to a Beheading by Vladimir Nabokov. I loved the book, and I think I understand the problems of most, but had some questions about the finale. Is this the end of the book, literally, or taken as a metaphor? It was this world she lived in Cincinnati, also real, or has always been an illusion? Like Nabokov finally wanted to talk about the society and the reality as a whole? Thank you!