Well, Einstein is clearly important. The novel might have shown how his fame and his scientific achievements affected his relationship with Mileva. It could have explored his inner thoughts and how he balanced his personal and professional lives.
There might be other characters such as their friends, colleagues, or family members. For example, their children could be part of the story, showing the family dynamic within the context of Einstein's busy scientific life.
It's likely about an aspect of Einstein's life or a fictional take related to him. Maybe it explores the life of someone in Einstein's orbit that we don't usually hear about.
Well, it's a blend of fact and fiction. The story might draw inspiration from real people and events, but it's likely embellished and adapted for a more engaging narrative.