Synthesized answer
The provided passages do not contain information that answers the question about what questions remain unanswered. The passages only offer the title of the book and its author, along with a list of other works by the same author [1]. Therefore, it is not possible to determine what questions remain unanswered based on the given text.
Synthesized from the book passages below. Chat with the book on Feynman for follow-up.
From the book
Title: Dostoyevsky. Notes From Underground / White Nights / The Dream of a Ridiculous Man / Selections from The House of the Dead by Фёдор Михайлович Достоевский